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  • 451.
    Negi, Devendra Singh
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Spiegelberg, Jakob
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Muto, Shunsuke
    Nagoya Univ, Elect Nanoscopy Sect, Adv Measurement Technol Ctr, Inst Mat & Syst Sustainabil,Chikusa Ku, Furo Cho, Nagoya, Aichi 4648603, Japan.
    Thersleff, Thomas
    Stockholm Univ, Dept Mat & Environm Chem, Svante Arrhenius Vag 16C, S-10691 Stockholm, Sweden.
    Ohtsuka, Masahiro
    Nagoya Univ, Grad Sch Engn, Dept Mat Phys, Chikusa Ku, Furo Cho, Nagoya, Aichi 4648603, Japan.
    Schonstrom, Linus
    Stockholm Univ, Dept Mat & Environm Chem, Svante Arrhenius Vag 16C, S-10691 Stockholm, Sweden.
    Tatsumi, Kazuyoshi
    Nagoya Univ, Inst Mat & Syst Sustainabil, Adv Measurement Technol Ctr, Chikusa Ku, Nagoya, Aichi 4648603, Japan.
    Rusz, Jan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Proposal for Measuring Magnetism with Patterned Apertures in a Transmission Electron Microscope2019Inngår i: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 122, nr 3, artikkel-id 037201Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We propose a magnetic measurement method utilizing a patterned postsample aperture in a transmission electron microscope. While utilizing electron magnetic circular dichroism, the method circumvents previous needs to shape the electron probe to an electron vortex beam or astigmatic beam. The method can be implemented in standard scanning transmission electron microscopes by replacing the spectrometer entrance aperture with a specially shaped aperture, hereafter called a ventilator aperture. The proposed setup is expected to work across the whole range of beam sizes-from wide parallel beams down to atomic resolution magnetic spectrum imaging.

  • 452.
    Nicolis, Stamatios C.
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Matematiska institutionen.
    Fernandez, J.
    Perez-Penichet, C.
    Noda, C.
    Tejera, F.
    Ramos, O.
    Sumpter, David J. T.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Matematiska institutionen.
    Altshuler, E.
    Foraging at the Edge of Chaos: Internal Clock versus External Forcing2013Inngår i: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 110, nr 26, s. 268104-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Activity rhythms in animal groups arise both from external changes in the environment, as well as from internal group dynamics. These cycles are reminiscent of physical and chemical systems with quasiperiodic and even chaotic behavior resulting from "autocatalytic'' mechanisms. We use nonlinear differential equations to model how the coupling between the self-excitatory interactions of individuals and external forcing can produce four different types of activity rhythms: quasiperiodic, chaotic, phase locked, and displaying over or under shooting. At the transition between quasiperiodic and chaotic regimes, activity cycles are asymmetrical, with rapid activity increases and slower decreases and a phase shift between external forcing and activity. We find similar activity patterns in ant colonies in response to varying temperature during the day. Thus foraging ants operate in a region of quasiperiodicity close to a cascade of transitions leading to chaos. The model suggests that a wide range of temporal structures and irregularities seen in the activity of animal and human groups might be accounted for by the coupling between collectively generated internal clocks and external forcings.

  • 453.
    Norgren, Cecilia
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutet för rymdfysik, Uppsalaavdelningen. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Rymd- och plasmafysik.
    Vaivads, Andris
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutet för rymdfysik, Uppsalaavdelningen.
    Khotyaintsev, Yuri V.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutet för rymdfysik, Uppsalaavdelningen.
    André, Mats
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutet för rymdfysik, Uppsalaavdelningen.
    Lower Hybrid Drift Waves: Space Observations2012Inngår i: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 109, nr 5, s. 055001-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Lower hybrid drift waves (LHDWs) are commonly observed at plasma boundaries in space and laboratory, often having the strongest measured electric fields within these regions. We use data from two of the Cluster satellites (C3 and C4) located in Earth's magnetotail and separated by a distance of the order of the electron gyroscale. These conditions allow us, for the first time, to make cross-spacecraft correlations of the LHDWs and to determine the phase velocity and wavelength of the LHDWs. Our results are in good agreement with the theoretical prediction. We show that the electrostatic potential of LHDWs is linearly related to fluctuations in the magnetic field magnitude, which allows us to determine the velocity vector through the relation integral delta Edt . v = phi(delta B parallel to). The electrostatic potential fluctuations correspond to similar to 10% of the electron temperature, which suggests that the waves can strongly affect the electron dynamics.

  • 454.
    Norin, Lars
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutet för rymdfysik, Uppsalaavdelningen.
    Leyser, Thomas
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutet för rymdfysik, Uppsalaavdelningen.
    Nordblad, Erik
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutet för rymdfysik, Uppsalaavdelningen.
    Thidé, Bo
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutet för rymdfysik, Uppsalaavdelningen.
    McCarrick, M.
    Unprecedentedly strong and narrow electromagnetic emissions stimulated by high-frequency radio waves in the ionosphere2009Inngår i: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 102, nr 6, s. 065003-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Experimental results of secondary electromagnetic radiation, stimulated by high-frequency radio waves irradiating the ionosphere, are reported. We have observed emission peaks, shifted in frequency up to a few tens of Hertz from radio waves transmitted at several megahertz. These emission peaks are by far the strongest spectral features of secondary radiation that have been reported. The emissions are attributed to stimulated Brillouin scattering, long predicted but hitherto never unambiguously identified in high-frequency ionospheric interaction experiments. The experiments were performed at the High-Frequency Active Auroral Research Program (HAARP), Alaska, USA.

  • 455.
    Pauli, S.
    et al.
    Paul Scherrer Institut.
    Leake, S.
    Paul Scherrer Institut.
    Delley, B.
    Paul Scherrer Institut.
    Björck, M.
    Paul Scherrer Institut.
    Schneider, C.
    Paul Scherrer Institut.
    Schlepütz, C.
    Paul Scherrer Institut.
    Martoccia, D.
    Paul Scherrer Institut.
    Paetel, S.
    University of Augsburg.
    Mannhart, J.
    University of Augsburg.
    Willmott, P.
    Paul Scherrer Institut.
    Evolution of the Interfacial Structure of LaAlO3 on SrTiO32011Inngår i: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 106, s. 1-4Artikkel i tidsskrift (Fagfellevurdert)
  • 456.
    Pedersen, M O
    et al.
    University of Aarhus, Aarhus, Denmarkv.
    Österlund, Lars
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Mortensen, J J
    University of Aarhus, Aarhus, Denmark.
    Mavrikakis, M
    Danish Technical University, Lyngby, Denmark.
    Hansen, L B
    Danish Technical University, Lyngby, Denmark.
    Stensgaard, I
    University of Aarhus, Aarhus, Denmark.
    Laegsgaard, E
    University of Aarhus, Aarhus, Denmark.
    Norskov, J K
    Danish Technical University, Lyngby, Denmark.
    Besenbacher, F
    University of Aarhus, Aarhus, Denmark.
    Diffusion of N adatoms on the Fe(100) surface2000Inngår i: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 84, nr 21, s. 4898-4901Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The diffusion of individual N adatoms on Fe(100) has been studied using scanning tunneling microscopy and ab initio density functional theory (DFT) calculations. The measured diffusion barrier for isolated N adatoms is E-d = (0.92 +/- 0.04) eV, with a prefactor of nu(0) = 4.3 x 10(12) s(-1), which is in quantitative agreement with the DFT calculations. Thr; diffusion is strongly coupled to lattice distortions. and. as a consequence, the presence of other N adatoms introduces an anisotropy in the diffusion. Based on experimentally determined values of the diffusion barriers and adsorbate-adsorbate: interactions, the potential energy surface experienced by a N adatom is determined.

  • 457.
    Pershoguba, Sergey S.
    et al.
    KTH Royal Inst Technol, Ctr Quantum Mat, Nordita, S-10691 Stockholm, Sweden.;Stockholm Univ, S-10691 Stockholm, Sweden..
    Björnson, Kristofer
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Black-Schaffer, Annica M.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Balatsky, Alexander V.
    KTH Royal Inst Technol, Ctr Quantum Mat, Nordita, S-10691 Stockholm, Sweden.;Stockholm Univ, S-10691 Stockholm, Sweden.;Los Alamos Natl Lab, Inst Mat Sci, Los Alamos, NM 87545 USA..
    Currents Induced by Magnetic Impurities in Superconductors with Spin-Orbit Coupling2015Inngår i: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 115, nr 11, artikkel-id 116602Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We show that superconducting currents are generated around magnetic impurities and ferromagnetic islands proximity coupled to superconductors with finite spin-orbit coupling. Using the Ginzburg-Landau theory, T-matrix calculation, as well as self-consistent numerical simulation on a lattice, we find a strong dependence of the current on the direction and magnitude of the magnetic moment. We establish that in the case of point magnetic impurities, the current is carried by the induced Yu-Shiba-Rusinov (YSR) subgap states. In the vicinity of the phase transition, where the YSR states cross at zero energy, the current increases dramatically. Furthermore, we show that the currents are orthogonal to the local spin polarization and, thus, can be probed by measuring the spin-polarized local density of states.

  • 458. Persson, Clas
    et al.
    Platzer-Björkman, Charlotte
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Malmström, Jonas
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Törndahl, Tobias
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Edoff, Marika
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektronik.
    Strong valence-band offset bowing of ZnO1-xSx enhances p-type nitrogen doping of ZnO-like alloys2006Inngår i: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 97, nr 14, s. 146403-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Photoelectron spectroscopy, optical characterization, and density functional calculations of ZnO1-xSx reveal that the valence-band (VB) offset E-v(x) increases strongly for small S content, whereas the conduction-band edge E-c(x) increases only weakly. This is explained as the formation of local ZnS-like bonds in the ZnO host, which mainly affects the VB edge and thereby narrows the energy gap: E-g(x=0.28)approximate to E-g(ZnO)-0.6 eV. The low-energy absorption tail is a direct Gamma(v)->Gamma(c) transition from ZnS-like VB. The VB bowing can be utilized to enhance p-type N-O doping with lower formation energy Delta H-f and shallower acceptor state in the ZnO-like alloys.

  • 459. Picozzi, S.
    et al.
    Yamauchi, K.
    Sanyal, Biplab
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Fysiska institutionen, Teoretisk magnetism.
    Sergienko, I. A.
    Dagotto, E.
    Dual nature of improper ferroelectricity in a magnetoelectric multiferroic2007Inngår i: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 99, nr 22, s. 227201-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Using first-principles calculations, we study the microscopic origin of ferroelectricity (FE) induced by magnetic order in the orthorhombic HoMnO3. We obtain the largest ferroelectric polarization observed in the whole class of improper magnetic ferroelectrics to date. We find that the two proposed mechanisms for FE in multiferroics, lattice and electronic based, are simultaneously active in this compound: a large portion of the ferroelectric polarization arises due to quantum-mechanical effects of electron orbital polarization, in addition to the conventional polar atomic displacements. An interesting mechanism for switching the magnetoelectric domains by an electric field via a 180 degrees coherent rotation of Mn spins is also proposed.

  • 460.
    Pietzsch, A.
    et al.
    MAX-lab, Lund University, Box 118, S-221 00 Lund, Sweden.
    Sun, Y. -P
    Department of Theoretical Chemistry and Biology, School of Biotechnology, Royal Institute of Technology, S-106 91 Stockholm, Sweden.
    Hennies, Franz
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Mjukröntgenfysik.
    Rinkevicius, Z.
    Department of Theoretical Chemistry and Biology, School of Biotechnology, Royal Institute of Technology, S-106 91 Stockholm, Sweden.
    Karlsson, Hans
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för fysikalisk och analytisk kemi, Kvantkemi.
    Schmitt, T.
    Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland.
    Strocov, V. N.
    Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland.
    Andersson, Joakim
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Mjukröntgenfysik.
    Kennedy, B.
    MAX-lab, Lund University, Box 118, S-221 00 Lund, Sweden.
    Schlappa, J.
    Institute for Methods and Instrumentation in Synchrotron Radiation Research G-I2, Helmholtz-Zentrum Berlin für Materialien und Energie, Albert-Einstein-Strasse 15, 12489 Berlin, Germany.
    Foehlisch, A.
    Institute for Methods and Instrumentation in Synchrotron Radiation Research G-I2, Helmholtz-Zentrum Berlin für Materialien und Energie, Albert-Einstein-Strasse 15, 12489 Berlin, Germany.
    Rubensson, Jan-Erik
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Mjukröntgenfysik.
    Gel'mukhanov, F.
    Department of Theoretical Chemistry and Biology, School of Biotechnology, Royal Institute of Technology, S-106 91 Stockholm, Sweden.
    Spatial Quantum Beats in Vibrational Resonant Inelastic Soft X-Ray Scattering at Dissociating States in Oxygen2011Inngår i: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 106, nr 15, s. 153004-1-153004-4Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Resonant inelastic soft x-ray scattering (RIXS) spectra excited at the 1 sigma(g) -> 3 sigma(u) resonance in gas-phase O-2 show excitations due to the nuclear degrees of freedom with up to 35 well-resolved discrete vibronic states and a continuum due to the kinetic energy distribution of the separated atoms. The RIXS profile demonstrates spatial quantum beats caused by two interfering wave packets with different momenta as the atoms separate. Thomson scattering strongly affects both the spectral profile and the scattering anisotropy.

  • 461. Puettner, Ralph
    et al.
    Goldsztejn, Gildas
    Ceolin, Denis
    Rueff, Jean-Pascal
    Moreno, Thierry
    Kushawaha, Rajesh K.
    Marchenko, Tatiana
    Guillemin, Renaud
    Journel, Loic
    Lindle, Dennis W.
    Piancastelli, Maria Novella
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Molekyl- och kondenserade materiens fysik.
    Simon, Marc
    Direct Observation of Double-Core-Hole Shake-Up States in Photoemission2015Inngår i: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 114, nr 9, artikkel-id 093001Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Direct measurements of Ar+ 1s(-1)2p(-1)nl double-core-hole shake-up states are reported using conventional single-channel photoemission, offering a new and relatively easy means to study such species. The high-quality results yield accurate energies and lifetimes of the double-core-hole states. Their photoemission spectrum also can be likened to 1s absorption of an exotic argon ion with a 2p core vacancy, providing new information about the spectroscopy of both this unusual ionic state as well as the neutral atom.

  • 462. Punkkinen, M. P. J.
    et al.
    Kwon, S. K.
    Kollar, J.
    Johansson, Börje
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Vitos, Levente
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Compressive Surface Stress in Magnetic Transition Metals2011Inngår i: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 106, nr 5, s. 057202-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Because of the increased electron density within the surface layer, metal surfaces are generally expected to have tensile surface stress. Here, using first-principles density functional calculations, we demonstrate that in magnetic 3d metals surface magnetism can alter this commonly accepted picture. We find that the thermodynamically stable surfaces of chromium and manganese possess compressive surface stress. The revealed negative surface stress is shown to be ascribed to the enhanced magnetic moments within the surface layer relative to the bulk values.

  • 463.
    Ramberg, Nicklas
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi.
    Sjöqvist, Erik
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori. Uppsala universitet.
    Environment-assisted holonomic quantum maps2019Inngår i: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 122, artikkel-id 140501Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Holonomic quantum computation uses non-Abelian geometric phases to realize error resilient quantum gates. Nonadiabatic holonomic gates are particularly suitable to avoid unwanted decoherence effects, as they can be performed at high speed. By letting the computational system interact with a structured environment, we show that the scope of error resilience of nonadiabatic holonomic gates can be widened to include systematic parameter errors. Our scheme maintains the geometric properties of the evolution and results in an environment-assisted holonomic quantum map that can mimic the effect of a holonomic gate. We demonstrate that the sensitivity to systematic errors can be reduced in a proof-of-concept spin-bath model.

  • 464. Ravasio, A
    et al.
    Gauthier, D
    Maia, F. R. N. C.
    Billon, M
    Caumes, J
    Garzella, D
    Geleoc, M
    Gobert, O
    Hergott, J
    Pena, A
    Perez, H
    Carre, B
    Bourhis, E
    Gierak, J
    Madouri, A
    Mailly, D
    Schiedt, B
    Fajardo, M
    Gautier, J
    Zeitoun, P
    Bucksbaum, P
    Hajdu, J
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för cell- och molekylärbiologi.
    Merdji, H
    Single-Shot Diffractive Imaging with a Table-Top Femtosecond Soft X-Ray Laser-Harmonics Source2009Inngår i: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 103, nr 2, s. 028104-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Coherent x-ray diffractive imaging is a powerful method for studies on   nonperiodic structures on the nanoscale. Access to femtosecond dynamics   in major physical, chemical, and biological processes requires   single-shot diffraction data. Up to now, this has been limited to   intense coherent pulses from a free electron laser. Here we show that   laser-driven ultrashort x-ray sources offer a comparatively inexpensive  alternative. We present measurements of single-shot diffraction patterns from isolated nano-objects with a single 20 fs pulse from a   table-top high-harmonic x-ray laser. Images were reconstructed with a   resolution of 119 nm from the single shot and 62 nm from multiple shots.

  • 465.
    Rojas González, Edgar Alonso
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik. Univ Paris Saclay, CNRS, Ctr Nanosci Nanotechnol, F-91460 Marcoussis, France.
    Borne, A.
    Boulanger, B.
    Levenson, J.A.
    Bencheikh, K.
    Continuous-Variable Triple-Photon States Quantum Entanglement2018Inngår i: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 120, nr 4, artikkel-id 043601Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We investigate the quantum entanglement of the three modes associated with the three-photon states obtained by triple-photon generation in a phase-matched third-order nonlinear optical interaction. Although the second-order processes have been extensively dealt with, there is no direct analogy between the second and third-order mechanisms. We show, for example, the absence of quantum entanglement between the quadratures of the three modes in the case of spontaneous parametric triple-photon generation. However, we show robust, seeding-dependent, genuine triple-photon entanglement in the fully seeded case.

  • 466.
    Roth, D.
    et al.
    Johannes Kepler Univ Linz, IEP AOP, Altenbergerstr 69, A-4040 Linz, Austria..
    Bruckner, B.
    Johannes Kepler Univ Linz, IEP AOP, Altenbergerstr 69, A-4040 Linz, Austria.;Univ Sao Paulo, Inst Fis, Rua Matao 1371, BR-05508090 Sao Paulo, Brazil..
    Moro, M. V.
    Johannes Kepler Univ Linz, IEP AOP, Altenbergerstr 69, A-4040 Linz, Austria..
    Gruber, S.
    Johannes Kepler Univ Linz, IEP AOP, Altenbergerstr 69, A-4040 Linz, Austria..
    Goebl, D.
    Johannes Kepler Univ Linz, IEP AOP, Altenbergerstr 69, A-4040 Linz, Austria..
    Juaristi, J. I.
    Donostia Int Phys Ctr DIPC, P Manuel De Lardizabal 4, San Sebastian 20018, Spain.;Univ Basque Country, CSIC, MPC, Ctr Fis Mat CFM, P Manuel De Lardizabal 5, Donostia San Sebastian 20018, Spain.;Univ Pais Vasco UPV EHU, Fac Quim, Dept Fis Mat, Apartado 1072, San Sebastian 20018, Spain..
    Alducin, M.
    Donostia Int Phys Ctr DIPC, P Manuel De Lardizabal 4, San Sebastian 20018, Spain.;Univ Basque Country, CSIC, MPC, Ctr Fis Mat CFM, P Manuel De Lardizabal 5, Donostia San Sebastian 20018, Spain..
    Steinberger, R.
    Johannes Kepler Univ Linz, Zentrum Oberflachen & Nanoanalyt ZONA, Christian Doppler Lab Microscop & Spectroscop Mat, Altenbergerstr 69, A-4040 Linz, Austria..
    Duchoslav, J.
    Johannes Kepler Univ Linz, Zentrum Oberflachen & Nanoanalyt ZONA, Christian Doppler Lab Microscop & Spectroscop Mat, Altenbergerstr 69, A-4040 Linz, Austria..
    Primetzhofer, Daniel
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Tillämpad kärnfysik.
    Bauer, P.
    Johannes Kepler Univ Linz, IEP AOP, Altenbergerstr 69, A-4040 Linz, Austria.;Donostia Int Phys Ctr DIPC, P Manuel De Lardizabal 4, San Sebastian 20018, Spain..
    Electronic Stopping of Slow Protons in Transition and Rare Earth Metals: Breakdown of the Free Electron Gas Concept2017Inngår i: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 118, nr 10, artikkel-id 103401Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The electronic stopping cross sections (SCS) of Ta and Gd for slow protons have been investigated experimentally. The data are compared to the results for Pt and Au to learn how electronic stopping in transition and rare earth metals correlates with features of the electronic band structures. The extraordinarily high SCS observed for protons in Ta and Gd cannot be understood in terms of a free electron gas model, but are related to the high densities of both occupied and unoccupied electronic states in these metals.

  • 467.
    Roth, D.
    et al.
    Johannes Kepler Univ Linz, IEP AOP, Altenbergerstr 69, A-4040 Linz, Austria..
    Bruckner, B.
    Johannes Kepler Univ Linz, IEP AOP, Altenbergerstr 69, A-4040 Linz, Austria..
    Undeutsch, G.
    Johannes Kepler Univ Linz, IEP AOP, Altenbergerstr 69, A-4040 Linz, Austria..
    Paneta, Valentina
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Tillämpad kärnfysik.
    Mardare, A. I.
    Johannes Kepler Univ Linz, Inst Chem Technol Anorgan Stoffe, Altenbergerstr 69, A-4040 Linz, Austria..
    McGahan, C. L.
    Vanderbilt Univ, Dept Phys & Astron, Nashville, TN 37235 USA..
    Dosmailov, M.
    Johannes Kepler Univ Linz, Inst Angew Phys, Altenbergerstr 69, A-4040 Linz, Austria..
    Juaristi, J. I.
    DIPC, P Manuel de Lardizabal 4, Donostia San Sebastian 20018, Spain.;Ctr Fis Mat CFM MPC CSIC UPV EHU, P Manuel de Lardizabal 5, Donostia San Sebastian 20018, Spain.;Univ Pais Vasco UPV EHU, Dept Fis Mat, Fac Quim, Apartado 1072, Donostia San Sebastian 20018, Spain..
    Alducin, M.
    DIPC, P Manuel de Lardizabal 4, Donostia San Sebastian 20018, Spain.;Ctr Fis Mat CFM MPC CSIC UPV EHU, P Manuel de Lardizabal 5, Donostia San Sebastian 20018, Spain..
    Pedarnig, J. D.
    Johannes Kepler Univ Linz, Inst Angew Phys, Altenbergerstr 69, A-4040 Linz, Austria..
    Haglund, R. F., Jr.
    Vanderbilt Univ, Dept Phys & Astron, Nashville, TN 37235 USA..
    Primetzhofer, Daniel
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Tillämpad kärnfysik.
    Bauer, P.
    Johannes Kepler Univ Linz, IEP AOP, Altenbergerstr 69, A-4040 Linz, Austria.;DIPC, P Manuel de Lardizabal 4, Donostia San Sebastian 20018, Spain..
    Electronic Stopping of Slow Protons in Oxides: Scaling Properties2017Inngår i: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 119, nr 16, artikkel-id 163401Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Electronic stopping of slow protons in ZnO, VO2 (metal and semiconductor phases), HfO2, and Ta2O5 was investigated experimentally. As a comparison of the resulting stopping cross sections (SCS) to data for Al2O3 and SiO2 reveals, electronic stopping of slow protons does not correlate with electronic properties of the specific material such as band gap energies. Instead, the oxygen 2p states are decisive, as corroborated by density functional theory calculations of the electronic densities of states. Hence, at low ion velocities the SCS of an oxide primarily scales with its oxygen density.

  • 468.
    Rubensson, Jan-Erik
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Fysiska institutionen.
    Såthe, Conny
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Fysiska institutionen.
    Cramm, S
    Kessler, B
    Stranges, S
    Richter, R
    Alagia, M
    Coreno, M
    Influence of the Radiative Decay on the Cross Section for Double Excitations in Helium1999Inngår i: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 83, nr 5, s. 947-950Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The fluorescence yield spectrum of the double excitations in helium has been measured. All three Rydberg series converging to the N = 2 threshold are resolved, and the intensity of the individual lines is determined. The intensity variation through each series indicates that the radiative decay channel cannot be neglected when discussing the double excitations in helium. This calls for a revision of the interpretation of the absorption spectrum, and sets the limit for using the ion yield method to monitor the absorption probability.

  • 469.
    Rubensson, Jan-Erik
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Molekyl- och kondenserade materiens fysik.
    Söderström, Johan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Molekyl- och kondenserade materiens fysik.
    Binggeli, Christian
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi.
    Gråsjö, Johan
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Farmaceutiska fakulteten, Institutionen för farmaci.
    Andersson, Joakim
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Molekyl- och kondenserade materiens fysik.
    Sathe, C.
    Hennies, F.
    Bisogni, V.
    Huang, Y.
    Olalde, P.
    Schmitt, T.
    Strocov, V. N.
    Fohlisch, A.
    Kennedy, B.
    Pietzsch, A.
    Rydberg-Resolved Resonant Inelastic Soft X-Ray Scattering: Dynamics at Core Ionization Thresholds2015Inngår i: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 114, nr 13, artikkel-id 133001Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Resonant inelastic x-ray scattering spectra excited in the immediate vicinity of the core-level ionization thresholds of N-2 have been recorded. Final states of well-resolved symmetry-selected Rydberg series converging to valence-level ionization thresholds with vibrational excitations are observed. The results are well described by a quasi-two-step model which assumes that the excited electron is unaffected by the radiative decay. This threshold dynamics simplifies the interpretation of resonant inelastic x-ray scattering spectra considerably and facilitates characterization of low-energy excited final states in molecular systems.

  • 470.
    Rung, Andreas
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Ribbing, Carl G.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Polaritonic and Photonic Gap Interactions in a Two-Dimensional Photonic Crystal2004Inngår i: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 92, nr 12, s. 123901.1-123901.4Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    If an ionic material is used in a photonic crystal, the lattice resonance creates a polaritonic gap in the infrared range. The interaction between a polaritonic gap and the structure gap in a 2D square photonic crystal is studied by transfer matrix photonic band structure calculations. The polaritonic gap appears for a surprisingly low volume density of the ionic material. The TM gaps are larger than the TE gaps, as in the dielectric case. By varying the lattice constant, the structure gaps can be shifted across the polaritonic gap, and the effects of merging the two gaps can be studied.

  • 471.
    Rusz, Jan
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Bhowmick, Somnath
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Boundaries for Efficient Use of Electron Vortex Beams to Measure Magnetic Properties2013Inngår i: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 111, nr 10, s. 105504-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Development of experimental techniques for characterization of magnetic properties at high spatial resolution is essential for progress in miniaturization of magnetic devices, for example, in data storage media. Inelastic scattering of electron vortex beams (EVBs) was recently reported to contain atom-specific magnetic information. We develop a theoretical description of inelastic scattering of EVBs on crystals and perform simulations for EVBs of different diameters. We show that use of an EVB wider than an interatomic distance does not provide any advantage over an ordinary convergent beam without angular momentum. On the other hand, in the atomic-resolution limit, electron energy loss spectra measured by EVBs are strongly sensitive to the spin and orbital magnetic moments of studied matter, when channeling through or very close to the atomic columns. Our results demonstrate the boundaries for efficient use of EVBs in measurement of magnetic properties.

  • 472.
    Rusz, Jan
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Idrobo, Juan-Carlos
    Bhowmick, Somnath
    Achieving Atomic Resolution Magnetic Dichroism by Controlling the Phase Symmetry of an Electron Probe2014Inngår i: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 113, nr 14, s. 145501-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The calculations presented here reveal that an electron probe carrying orbital angular momentum is just a particular case of a wider class of electron beams that can be used to measure electron magnetic circular dichroism (EMCD) with atomic resolution. It is possible to obtain an EMCD signal with atomic resolution by simply breaking the symmetry of the electron probe phase distribution using the aberration-corrected optics of a scanning transmission electron microscope. The required phase distribution of the probe depends on the magnetic symmetry and crystal structure of the sample. The calculations indicate that EMCD signals utilizing the phase of the electron probe are as strong as those obtained by nanodiffraction methods.

  • 473. Sa, Baisheng
    et al.
    Zhou, Jian
    Sun, Zhimei
    Tominaga, Junji
    Ahuja, Rajeev
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Topological Insulating in GeTe/Sb2Te3 Phase-Change Superlattice2012Inngår i: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 109, nr 9, s. 096802-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    GeTe/Sb2Te3 superlattice phase-change memory devices demonstrated greatly improved performance over that of Ge2Sb2Te5, a prototype record media for phase-change random access memory. In this work, we show that this type of GeTe/Sb2Te3 superlattice exhibits topological insulating behavior on the basis of ab initio calculations. The analysis of the band structures and parities as well as Z(2) topological invariants unravels the topological insulating nature in these artificial materials. Furthermore, the topological insulating character remains in the GeTe/Sb2Te3 superlattice under small compressive strains, whereas it is not observed as more Sb2Te3 building blocks introduced in the superlattice. The present results show that multifunctional data storages may be achieved in the GeTe/Sb2Te3 superlattice. Such kinds of artificial materials can be used in phase-change random access memory, spintronics, and quantum computing.

  • 474. Saenz, Alejandro
    et al.
    Jonsell, Svante
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kvantkemi.
    Froelich, Piotr
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Fysiska institutionen. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kvantkemi. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för fysikalisk och analytisk kemi, Kvantkemi.
    Improved molecular final-state distribution of HeT+ for the beta-decay process of T-22000Inngår i: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 84, nr 2, s. 242-245Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    An improved theoretical final-state distribution of HeT+ (and HeH+) resulting front the beta decay of molecular tritium T-2 (HT) is presented to accommodate the needs of increased accuracy in the analysis of ongoing and future tritium neutrino-mass experiments. The previously available theoretical spectrum has been improved in many respects, and adopted approximations have been validated.

  • 475. Sahraoui, F.
    et al.
    Goldstein, M. L.
    Robert, P.
    Khotyaintsev, Yuri
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutet för rymdfysik, Uppsalaavdelningen.
    Evidence of a Cascade and Dissipation of Solar-Wind Turbulence at the Electron Gyroscale2009Inngår i: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 102, nr 23, s. 231102-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We report the first direct determination of the dissipation range of magnetofluid turbulence in the solar wind at the electron scales. Combining high resolution magnetic and electric field data of the Cluster spacecraft, we computed the spectrum of turbulence and found two distinct breakpoints in the magnetic spectrum at 0.4 and 35 Hz, which correspond, respectively, to the Doppler-shifted proton and electron gyroscales, f(rho p) and f(rho e). Below f(rho p), the spectrum follows a Kolmogorov scaling f(-1.62), typical of spectra observed at 1 AU. Above f(rho p), a second inertial range is formed with a scaling f(-2.3) down to f(rho e). Above f(rho e), the spectrum has a steeper power law similar to f(-4.1) down to the noise level of the instrument. We interpret this as the dissipation range and show a remarkable agreement with theoretical predictions of a quasi-two-dimensional cascade into Kinetic Alfveacuten Waves (KAW).

  • 476. Sahraoui, F.
    et al.
    Robert, P.
    Goldstein, M. L.
    Khotyaintsev, Yuri V.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutet för rymdfysik, Uppsalaavdelningen.
    Comment on "Evidence of a Cascade and Dissipation of Solar-Wind Turbulence at the Electron Gyroscale" Reply2013Inngår i: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 111, nr 14, s. 149002-Artikkel i tidsskrift (Annet vitenskapelig)
  • 477. Salen, P.
    et al.
    van der Meulen, P.
    Schmidt, H. T.
    Thomas, R. D.
    Larsson, M.
    Feifel, Raimund
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Mjukröntgenfysik.
    Piancastelli, Maria Novella
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Yt- och gränsskiktsvetenskap.
    Fang, L.
    Murphy, B.
    Osipov, T.
    Berrah, N.
    Kukk, E.
    Ueda, K.
    Bozek, J. D.
    Bostedt, C.
    Wada, S.
    Richter, R.
    Feyer, V.
    Prince, K. C.
    Experimental Verification of the Chemical Sensitivity of Two-Site Double Core-Hole States Formed by an X-Ray Free-Electron Laser2012Inngår i: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 108, nr 15, s. 153003-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We have performed x-ray two-photon photoelectron spectroscopy using the Linac Coherent Light Source x-ray free-electron laser in order to study double core-hole (DCH) states of CO2, N2O, and N2. The experiment verifies the theory behind the chemical sensitivity of two-site DCH states by comparing a set of small molecules with respect to the energy shift of the two-site DCH state and by extracting the relevant parameters from this shift.

  • 478. Sanchez-Barriga, J.
    et al.
    Fink, J.
    Boni, V.
    Di Marco, Igor
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och materialvetenskap, Materialteori.
    Braun, J.
    Minar, J.
    Varykhalov, A.
    Rader, O.
    Bellini, V.
    Manghi, F.
    Ebert, H.
    Katsnelson, M. I.
    Lichtenstein, A. I.
    Eriksson, Olle
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och materialvetenskap, Materialteori.
    Eberhardt, W.
    Duerr, H. A.
    Strength of Correlation Effects in the Electronic Structure of Iron2009Inngår i: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 103, nr 26, s. 267203-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The strength of electronic correlation effects in the spin-dependent electronic structure of ferromagnetic bcc Fe(110) has been investigated by means of spin and angle-resolved photoemission spectroscopy. The experimental results are compared to theoretical calculations within the three-body scattering approximation and within the dynamical mean-field theory, together with one-step model calculations of the photoemission process. This comparison indicates that the present state of the art many-body calculations, although improving the description of correlation effects in Fe, give too small mass renormalizations and scattering rates thus demanding more refined many-body theories including nonlocal fluctuations.

  • 479.
    Sanpera, A.
    et al.
    Institut de Cie `ncies Foto `niques, 08034 Barcelona, Spain;Institut für Theoretische Physik, Universität Hannover, D-30167 Hannover, Germany.
    Kantian, A.
    Institut für Theoretische Physik, Universität Hannover, D-30167 Hannover, Germany.
    Sanchez-Palencia, L.
    Institut für Theoretische Physik, Universität Hannover, D-30167 Hannover, Germany.
    Zakrzewski, J.
    Instytut Fizyki, Uniwersytet Jagiellon ´ski, PL-30-059 Krako ´w, Poland.
    Lewenstein, M.
    Institut de Cie `ncies Foto `niques, 08034 Barcelona, Spain;Institut für Theoretische Physik, Universität Hannover, D-30167 Hannover, Germany.
    Atomic Fermi-Bose Mixtures in Inhomogeneous and Random Lattices: From Fermi Glass to Quantum Spin Glass and Quantum Percolation2004Inngår i: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 93, nr 4Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We investigate strongly interacting atomic Fermi-Bose mixtures in inhomogeneous and random optical lattices. We derive an effective Hamiltonian for the system and discuss its low temperature physics. We demonstrate the possibility of controlling the interactions at local level in inhomogeneous but regular lattices. Such a control leads to the achievement of Fermi glass, quantum Fermi spin-glass, and quantum percolation regimes involving bare and/or composite fermions in random lattices.

  • 480.
    Sanyal, Biplab
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi.
    Antoniak, Carolin
    Burkert, Till
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi.
    Krumme, Bernhard
    Warland, Anne
    Stromberg, Frank
    Praetorius, Christian
    Fauth, Kai
    Wende, Heiko
    Eriksson, Olle
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi.
    Forcing Ferromagnetic Coupling Between Rare-Earth-Metal and 3d Ferromagnetic Films2010Inngår i: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 104, nr 15, s. 156402-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Using density functional calculations, we have studied the magnetic properties of nanocomposites composed of rare-earth-metal elements in contact with 3d transition metals (Fe and Cr). We demonstrate the possibility to obtain huge magnetic moments in such nanocomposites, of order 10 mu(B)/rare-earth-metal atom, with a potential to reach the maximum magnetic moment of Fe-Co alloys at the top of the so-called Slater-Pauling curve. A first experimental proof of concept is given by thin-film synthesis of Fe/Gd and Fe/Cr/Gd nanocomposites, in combination with x-ray magnetic circular dichroism.

  • 481. Schoebel, Harald
    et al.
    Bartl, Peter
    Leidlmair, Christian
    Daxner, Matthias
    Zoettl, Samuel
    Denifl, Stephan
    Maerk, Tilmann D.
    Scheier, Paul
    Spångberg, Daniel
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi, Strukturkemi.
    Mauracher, Andreas
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi, Strukturkemi.
    Bohme, Diethard K.
    Sequential Penning Ionization: Harvesting Energy with Ions2010Inngår i: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 105, nr 24, s. 243402-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We report the observation of the ejection of electrons caused by collisions of excited atoms with ions, rather than neutrals, leading to the production of doubly charged ions. Doping superfluid He droplets with methyl iodide and exposing them to electrons enhances the formation of doubly charged iodine atoms at the threshold for the production of two metastable He atoms. These observations point toward a novel ionization process where doubly charged ions are produced by sequential Penning ionization. In some cases, depending on the neutral target, the process also leads to a subsequent Coulomb explosion of the dopant.

  • 482. Schwerdtfeger, W
    et al.
    Thirolf, G
    Wimmer, K
    Habs, D
    Mach, H
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för kärn- och partikelfysik.
    Rodriguez, R
    Bildstein, V
    Egido, L
    Fraile, M
    Gernhaeuser, R
    Hertenberger, R
    Heyde, K
    Hoff, P
    Huebel, H
    Koester, U
    Kroell, T
    Kruecken, R
    Lutter, R
    Morgan, T
    Ring, P
    Shape Coexistence Near Neutron Number N=20: First Identification of the E0 Decay from the Deformed First Excited J(pi)=0(+) State in Mg-302009Inngår i: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 103, nr 1, s. 012501-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The 1789 keV state in Mg-30 was identified as the first excited 0(+) state via its electric monopole (E0) transition to the ground state. The measured small value of rho(2)(E0,0(2)(+)-> 0(1)(+))=(26.2 +/- 7.5)x10(-3) implies within a two-level model a small mixing of competing configurations with largely different intrinsic quadrupole deformation near the neutron shell closure at N=20. Axially symmetric configuration mixing calculations identify the ground state of Mg-30 to be based on neutron configurations below the N=20 shell closure, while the excited 0(+) state mainly consists of two neutrons excited into the nu 1f(7/2) orbital. The experimental result represents the first case where an E0 back decay from a strongly deformed second to the normal deformed first nuclear potential minimum well has been unambiguously identified, thus directly proving shape coexistence at the borderline of the much-debated "island of inversion."

  • 483. Semenoff, Gordon
    et al.
    Zarembo, Konstantin
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Teoretisk fysik.
    Holographic Schwinger Effect2011Inngår i: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 107, nr 17Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We study tunneling pair creation of W-Bosons by an external electric field on the Coulomb branch of N=4 supersymmetric Yang-Mills theory. We use AdS/CFT holography to find a generalization of Schwinger's formula for the pair production rate to the strong coupling, planar limit which includes the exchange of virtual massless particles to all orders. We find that the pair creation formula has an upper critical electric field beyond which the process is no longer exponentially suppressed. The value of the critical field is identical to that which occurs in the Born-Infeld action of probe D3-branes in the AdS5XS5 background.

  • 484. Sharma, S.
    et al.
    Dewhurst, J. K.
    Ambrosch-Draxl, C.
    Kurth, S.
    Helbig, N.
    Pittalis, S.
    Shallcross, S.
    Nordström, Lars
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Fysiska institutionen.
    Gross, E. K. U.
    First-principles approach to noncollinear magnetism: Towards spin dynamics2007Inngår i: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 98, nr 19, s. 196405-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A description of noncollinear magnetism in the framework of spin-density functional theory is presented for the exact exchange energy functional which depends explicitly on two-component spinor orbitals. The equations for the effective Kohn-Sham scalar potential and magnetic field are derived within the optimized effective potential (OEP) framework. With the example of a magnetically frustrated Cr monolayer it is shown that the resulting magnetization density exhibits much more noncollinear structure than standard calculations. Furthermore, a time-dependent generalization of the noncollinear OEP method is well suited for an ab initio description of spin dynamics. We also show that the magnetic moments of solids Fe, Co, and Ni are well reproduced.

  • 485. She, Jian-Huang
    et al.
    Fransson, Jonas
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Bishop, A. R.
    Balatsky, Alexander V.
    Inelastic Electron Tunneling Spectroscopy for Topological Insulators2013Inngår i: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 110, nr 2, s. 026802-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Inelastic electron tunneling spectroscopy is a powerful spectroscopy that allows one to investigate the nature of local excitations and energy transfer in the system of interest. We study inelastic electron tunneling spectroscopy for topological insulators and investigate the role of inelastic scattering on the Dirac node states on the surface of topological insulators. Local inelastic scattering is shown to significantly modify the Dirac node spectrum. In the weak coupling limit, peaks and steps are induced in second derivative d(2)I/dV(2). In the strong coupling limit, the local negative-U centers are formed at impurity sites, and the Dirac cone structure is fully destroyed locally. At intermediate coupling, resonance peaks emerge. We map out the evolution of the resonance peaks from weak to strong coupling, which interpolate nicely between the two limits. There is a sudden qualitative change of behavior at intermediate coupling, indicating the possible existence of a local quantum phase transition. We also find that, even for a simple local phonon mode, the inherent coupling of spin and orbital degrees in topological insulators leads to the spin-polarized texture in inelastic Friedel oscillations induced by the local mode.

  • 486. Singh, B. S. Nara
    et al.
    Liu, Z.
    Wadsworth, R.
    Grawe, H.
    Brock, T. S.
    Boutachkov, P.
    Braun, N.
    Blazhev, A.
    Gorska, M.
    Pietri, S.
    Rudolph, D.
    Domingo-Pardo, C.
    Steer, S. J.
    Atac, A.
    Bettermann, L.
    Caceres, L.
    Eppinger, K.
    Engert, T.
    Faestermann, T.
    Farinon, F.
    Finke, F.
    Geibel, K.
    Gerl, J.
    Gernhaeuser, R.
    Goel, N.
    Gottardo, A.
    Grebosz, J.
    Hinke, C.
    Hoischen, R.
    Ilie, G.
    Iwasaki, H.
    Jolie, J.
    Kaskas, A.
    Kojouharov, I.
    Kruecken, R.
    Kurz, N.
    Merchan, E.
    Nociforo, C.
    Nyberg, Johan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Kärnfysik.
    Pfuetzner, M.
    Prochazka, A.
    Podolyak, Zs.
    Regan, P. H.
    Reiter, P.
    Rinta-Antila, S.
    Scholl, C.
    Schaffner, H.
    Söderström, Per-Anders
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Kärnfysik.
    Warr, N.
    Weick, H.
    Wollersheim, H. -J
    Woods, P. J.
    Nowacki, F.
    Sieja, K.
    16(+) Spin-Gap Isomer in (96)Cd2011Inngår i: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 107, nr 17, s. 172502-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A beta-decaying high-spin isomer in (96)Cd, with a half-life T(1/2) = 0.29(-0.10)(+0.11) s, has been established in a stopped beam rare isotope spectroscopic investigations at GSI (RISING) experiment. The nuclei were produced using the fragmentation of a primary beam of (124)Xe on a (9)Be target. From the half-life and the observed gamma decays in the daughter nucleus, (96)Ag, we conclude that the beta-decaying state is the long predicted 16(+) "spin-gap'' isomer. Shell-model calculations, using the Gross-Frenkel interaction and the pi nu(p(1/2,)g(9/2)) model space, show that the isoscalar component of the neutron-proton interaction is essential to explain the origin of the isomer. Core excitations across the N = Z = 50 gaps and the Gamow-Teller strength, Bd(GT) distributions have been studied via large-scale shell-model calculations using the pi nu(g, d, s) model space to compare with the experimental B(GT) value obtained from the half-life of the isomer.

  • 487.
    Sjöqvist, Erik
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Fysikalisk-kemiska institutionen, Avdelningen för kvantkemi.
    Locality and topology in the molecular Aharonov-Bohm effect2002Inngår i: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 89, nr 21, s. 210401-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    It is shown that the molecular Aharonov-Bohm effect is neither nonlocal nor topological in the sense of the standard magnetic Aharonov-Bohm effect. It is further argued that there is a close relationship between the molecular Aharonov-Bohm effect and the Aharonov-Casher effect for an electrically neutral spin-1/2 particle encircling a line of charge.

  • 488.
    Sjöqvist, Erik
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för fysikalisk och analytisk kemi, Kvantkemi.
    Reply to Comment on `Locality and topology in the molecular Aharonov-Bohm effect'2003Inngår i: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 91, nr 4, s. 048902-048902Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A Reply to the Comment by R. Resta in [Phys. Rev. Lett. 91, 048901 (2003)] on the Letter in [Phys. Rev. Lett. 89, 210401 (2002)].

  • 489.
    Sjöqvist, Erik
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kvantkemi.
    Pati, Arun K
    School of Informatics, Univ. of Wales, Bangor, UK .
    Ekert, Artur
    Centre for Quantum Computation, Clarendon Laboratory, Univ. of Oxford, UK.
    Anandan, Jeeva S.
    Dept. of Physics and Astronomy, Univ. of South Carolina, USA.
    Ericsson, Marie
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kvantkemi.
    Oi, Daniel K.L.
    Centre for Quantum Computation, Clarendon Laboratory, Univ. of Oxford, UK.
    Vedral, Vlatko
    Centre for Quantum Computation, Clarendon Laboratory, Univ. of Oxford, UK.
    Geometric phases for mixed states in interferometry2000Inngår i: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 85, nr 14, s. 2845-2849Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We provide a physical prescription based on interferometry for introducing the total phase of a mixed state undergoing unitary evolution, which has been an elusive concept in the past. We define the parallel transport condition that provides a connection form for obtaining the geometric phase for mixed states. The expression for the geometric phase for mixed state reduces to well known formulas in the pure state case when a system undergoes noncyclic and unitary quantum evolution.

  • 490.
    Sjöstedt, Elisabeth
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Fysiska institutionen.
    Nordström, Lars
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Fysiska institutionen.
    Gustavsson, Fredrik
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Fysiska institutionen.
    Eriksson, Olle
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Fysiska institutionen.
    Uniaxial magnetocrystalline anisotropy of metal/semiconductor interfaces: Fe/ZnSe(001)2002Inngår i: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 89, nr 26, s. 267203-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A theoretical study of the magnetic moments and the in-plane magnetic anisotropy of an interface between a cubic ferromagnet and a cubic semiconductor, Fe/ZnSe(001), is presented. Theory confirms the observed, much debated, uniaxial anisotropy of the iron film. This result is important since the calculations are for perfect interfaces with squarelike environments, proving that the fourfolded symmetry of the interface Fe atoms is broken beyond the nearest neighboring semiconducting layer, effects that are usually assumed small. It is demonstrated how the uniaxial anisotropy is produced by the directional covalent bonds at the interface, even without atomic relaxations.

  • 491.
    Skubic, Björn
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Fysiska institutionen.
    Holmström, Erik
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Fysiska institutionen.
    Iusan, Diana
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Fysiska institutionen.
    Bengone, Olivier
    Eriksson, Olle
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Fysiska institutionen.
    Brucas, Rimantas
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Fysiska institutionen.
    Hjörvarsson, Björgvin
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Fysiska institutionen.
    Stanciu, Victor
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Nordblad, Per
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Competing Exchange Interactions in Magnetic Multilayers2006Inngår i: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 96, s. 057205-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We have studied alloying of the nonmagnetic spacer layer with a magnetic material as a method of tuning the interlayer coupling in magnetic multilayers. We have specifically studied the Fe/V(100) system by alloying the spacer V with various amounts of Fe. For some Fe concentrations in the spacer, it is possible to create a competition between antiferromagnetic Ruderman-Kittel-Kasuya-Yoshida exchange and direct ferromagnetic exchange coupling. The exchange coupling and transport properties for a large span of systems with different spacer concentrations and thicknesses were calculated and measured experimentally and good agreement between observations and theory was observed. A reduction in magnetoresistance of about 50% was observed close to the switchover from antiferromagnetic to ferromagnetic coupling.

  • 492.
    Sorriso-Valvo, Luca
    et al.
    UOS Cosenza, Nanotec CNR, Cubo 31C, I-87036 Arcavacata Di Rende, Italy;Escuela Politec Nacl, Dept Fis, Quito 170517, Ecuador.
    Catapano, Filomena
    Univ Calabria, Dipartimento Fis, Cubo 31C, I-87036 Arcavacata Di Rende, Italy;Sorbonne Univ, Ecole Polytech, CNRS, LPP, F-91128 Palaiseau, France.
    Retino, Alessandro
    Sorbonne Univ, Ecole Polytech, CNRS, LPP, F-91128 Palaiseau, France.
    Le Contel, Olivier
    Sorbonne Univ, Ecole Polytech, CNRS, LPP, F-91128 Palaiseau, France.
    Perrone, Denise
    Imperial Coll London, Dept Phys, London SW7 2AZ, England.
    Roberts, Owen W.
    Austrian Acad Sci, Space Res Inst, Schmiedlstr 6, A-8042 Graz, Austria.
    Coburn, Jesse T.
    Univ Calabria, Dipartimento Fis, Cubo 31C, I-87036 Arcavacata Di Rende, Italy.
    Panebianco, Vincenzo
    Univ Calabria, Dipartimento Fis, Cubo 31C, I-87036 Arcavacata Di Rende, Italy.
    Valentini, Francesco
    Univ Calabria, Dipartimento Fis, Cubo 31C, I-87036 Arcavacata Di Rende, Italy.
    Perri, Silvia
    Univ Calabria, Dipartimento Fis, Cubo 31C, I-87036 Arcavacata Di Rende, Italy.
    Greco, Antonella
    Univ Calabria, Dipartimento Fis, Cubo 31C, I-87036 Arcavacata Di Rende, Italy.
    Malara, Francesco
    Univ Calabria, Dipartimento Fis, Cubo 31C, I-87036 Arcavacata Di Rende, Italy.
    Carbone, Vincenzo
    Univ Calabria, Dipartimento Fis, Cubo 31C, I-87036 Arcavacata Di Rende, Italy.
    Veltri, Pierluigi
    Univ Calabria, Dipartimento Fis, Cubo 31C, I-87036 Arcavacata Di Rende, Italy.
    Pezzi, Oreste
    Univ Calabria, Dipartimento Fis, Cubo 31C, I-87036 Arcavacata Di Rende, Italy;Gran Sasso Sci Inst, Viale F Crispi 7, I-67100 Laquila, Italy.
    Fraternale, Federico
    Politecn Torino, Dipartimento Sci Applicata & Tecnol, I-10129 Turin, Italy.
    Di Mare, Francesca
    Univ Oslo, Dept Phys, Sem Saelands Vei 26, N-0371 Oslo, Norway.
    Marino, Raffaele
    Univ Claude Bernard Lyon 1, Ecole Cent Lyon, INSA Lyon, Lab Mecan Fluides & Acoust,CNRS, F-69134 Ecully, France.
    Giles, Barbara
    NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA.
    Moore, Thomas E.
    NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA.
    Russell, Christopher T.
    Univ Calif Los Angeles, Inst Geophys & Planetary Phys, Los Angeles, CA 90095 USA;Univ Calif Los Angeles, Dept Earth Planetary & Space Sci, Los Angeles, CA 90095 USA.
    Torbert, Roy B.
    Univ New Hampshire, Space Sci Ctr, Durham, NH 03824 USA.
    Burch, Jim L.
    Southwest Res Inst, San Antonio, TX 78238 USA.
    Khotyaintsev, Yuri V.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutet för rymdfysik, Uppsalaavdelningen.
    Turbulence-Driven Ion Beams in the Magnetospheric Kelvin-Helmholtz Instability2019Inngår i: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 122, nr 3, artikkel-id 035102Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The description of the local turbulent energy transfer and the high-resolution ion distributions measured by the Magnetospheric Multiscale mission together provide a formidable tool to explore the cross-scale connection between the fluid-scale energy cascade and plasma processes at subion scales. When the small-scale energy transfer is dominated by Alfvenic, correlated velocity, and magnetic field fluctuations, beams of accelerated particles are more likely observed. Here, for the first time, we report observations suggesting the nonlinear wave-particle interaction as one possible mechanism for the energy dissipation in space plasmas.

  • 493.
    Souvatzis, Petros
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Fysiska institutionen.
    Eriksson, Olle
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Fysiska institutionen.
    Katsnelson, Mikhail
    Anomalous Thermal Expansion in α-Titanium2007Inngår i: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 99, nr 1, s. 015901-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We provide a complete quantitative explanation for the anisotropic thermal expansion of hcp Ti at low temperature. The observed negative thermal expansion along the c axis is reproduced theoretically by means of a parameter free theory which involves both the electron and phonon contributions to the free energy. The thermal expansion of titanium is calculated and found to be negative along the c axis for temperatures below ∼170 K, in good agreement with observations. We have identified a saddle point van Hove singularity near the Fermi level as the main reason for the anisotropic thermal expansion in α-titanium.

  • 494.
    Souvatzis, Petros
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Fysiska institutionen.
    Eriksson, Olle
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Fysiska institutionen.
    Katsnelson, Mikhail
    Rudin, Sven
    Entropy driven stabilization of energetically unstable crystal structures explained from first principles theory2008Inngår i: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 100, nr 9, s. 095901-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Conventional methods to calculate the thermodynamics of crystals evaluate the harmonic phonon spectra and therefore do not work in frequent and important situations where the crystal structure is unstable in the harmonic approximation, such as the body-centered cubic (bcc) crystal structure when it appears as a high-temperature phase of many metals. A method for calculating temperature dependent phonon spectra self-consistently from first principles has been developed to address this issue. The method combines concepts from Born's interatomic self-consistent phonon approach with first principles calculations of accurate interatomic forces in a supercell. The method has been tested on the high-temperature bcc phase of Ti, Zr, and Hf, as representative examples, and is found to reproduce the observed high-temperature phonon frequencies with good accuracy.

  • 495.
    Stamm, C.
    et al.
    Swiss Fed Inst Technol, Dept Mat, CH-8093 Zurich, Switzerland..
    Murer, C.
    Swiss Fed Inst Technol, Dept Mat, CH-8093 Zurich, Switzerland..
    Berritta, Marco
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Feng, J.
    Swiss Fed Inst Technol, Dept Mat, CH-8093 Zurich, Switzerland..
    Gabureac, M.
    Swiss Fed Inst Technol, Dept Mat, CH-8093 Zurich, Switzerland..
    Oppeneer, Peter M.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Gambardella, P.
    Swiss Fed Inst Technol, Dept Mat, CH-8093 Zurich, Switzerland..
    Magneto-Optical Detection of the Spin Hall Effect in Pt and W Thin Films2017Inngår i: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 119, nr 8, artikkel-id 087203Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The conversion of charge currents into spin currents in nonmagnetic conductors is a hallmark manifestation of spin-orbit coupling that has important implications for spintronic devices. Here we report the measurement of the interfacial spin accumulation induced by the spin Hall effect in Pt and W thin films using magneto-optical Kerr microscopy. We show that the Kerr rotation has opposite sign in Pt and W and scales linearly with current density. By comparing the experimental results with ab initio calculations of the spin Hall and magneto-optical Kerr effects, we quantitatively determine the current-induced spin accumulation at the Pt interface as 5×10−12  μB A−1 cm2 per atom. From thickness-dependent measurements, we determine the spin diffusion length in a single Pt film to be 11±3  nm, which is significantly larger compared to that of Pt adjacent to a magnetic layer.

  • 496.
    Ström, Magnus
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Fysiska institutionen.
    Såthe, Conny
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Fysiska institutionen.
    Agåker, Marcus
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Fysiska institutionen.
    Söderström, Johan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Fysiska institutionen.
    Rubensson, Jan-Erik
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Fysiska institutionen.
    Stranges, Stefano
    Richter, Robert
    Alagia, Michele
    Gorczyca, Tom
    Robicheaux, Francis
    Magnetic-field induced enhancement in the fluorescence yield spectrum of doubly excited states in helium2006Inngår i: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 97, nr 25, s. 253002-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    An influence of static magnetic fields on the fluorescence yield spectrum of He in the vicinity of the N=2 thresholds has been observed. The experimental results are in excellent agreement with predictions based on multichannel quantum defect theory, and it is demonstrated that the Rydberg electron ℓ mixing due to the diamagnetic interaction is essential for the description of the observed fluorescence yield intensity enhancement.

  • 497.
    Ström, Magnus
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Fysiska institutionen.
    Såthe, Conny
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Fysiska institutionen.
    Agåker, Marcus
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Fysiska institutionen.
    Söderström, Johan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Molekyl- och kondenserade materiens fysik.
    Rubensson, Jan-Erik
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Fysiska institutionen.
    Stranges, Stefano
    Richter, Robert
    Alagia, Michele
    Gorczyca, Tom
    Robicheaux, Francis
    Magnetic-field induced enhancement in the fluorescence yield spectrum of doubly excited states in helium2006Inngår i: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 97, nr 25, s. 253002-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    An influence of static magnetic fields on the fluorescence yield spectrum of He in the vicinity of the N=2 thresholds has been observed. The experimental results are in excellent agreement with predictions based on multichannel quantum defect theory, and it is demonstrated that the Rydberg electron ℓ mixing due to the diamagnetic interaction is essential for the description of the observed fluorescence yield intensity enhancement.

  • 498.
    Strømme, Maria
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Ahuja, Rajeev
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Fysiska institutionen. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Niklasson, Gunnar A.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    A new probe of the electron structure of amorphous materials2004Inngår i: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 93, nr 20, s. 206403-1Artikkel i tidsskrift (Fagfellevurdert)
  • 499.
    Stål, Oscar
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för kärn- och partikelfysik. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutet för rymdfysik, Uppsalaavdelningen.
    Bergman, Jan E.S.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutet för rymdfysik, Uppsalaavdelningen.
    Thidé, Bo
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutet för rymdfysik, Uppsalaavdelningen.
    Daldorff, Lars K.S.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutet för rymdfysik, Uppsalaavdelningen.
    Ingelman, Gunnar
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för kärn- och partikelfysik.
    Prospects for Lunar Satellite Detection of Radio Pulses from Ultrahigh Energy Neutrinos Interacting with the Moon2007Inngår i: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 98, nr 7, s. 071103-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The Moon provides a huge effective detector volume for ultrahigh energy cosmic neutrinos, which generate coherent radio pulses in the lunar surface layer due to the Askaryan effect. We report systematic Monte Carlo simulations which show that radio instruments on board a Moon-orbiting satellite can detect Askaryan pulses from neutrinos with energies above 10^{19} eV, i.e. near and above the interesting GZK limit, at the very low fluxes predicted in different scenarios.

  • 500. Sun, Y. -P
    et al.
    Miao, Q.
    Pietzsch, A.
    Hennies, F.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Molekyl- och kondenserade materiens fysik.
    Schmitt, T.
    Strocov, V. N.
    Andersson, Joakim
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Molekyl- och kondenserade materiens fysik.
    Kennedy, B.
    Schlappa, J.
    Foehlisch, A.
    Gel'mukhanov, F.
    Rubensson, Jan-Erik
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Molekyl- och kondenserade materiens fysik.
    Interference between Resonant and Nonresonant Inelastic X-Ray Scattering2013Inngår i: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 110, nr 22, s. 223001-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A detailed study of inelastic x-ray scattering from the ground state to the (3)Sigma(g)(3 sigma(-1)(g)3s(g)(1)) state of the O-2 molecule is presented. The observed angular anisotropy shows that the vibrational excitations within this final state are strongly dependent on the polarization of the incident radiation. The analysis demonstrates that this is a manifestation of interference between resonant and direct nonresonant inelastic x-ray scattering. This interference provides a new tool to monitor nuclear dynamics by relative rotation of the polarization vectors of the incident and scattered photons.

789101112 451 - 500 of 554
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