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Mårtensson, Nils
Alternative names
Publications (10 of 75) Show all publications
Kuehn, D., Mueller, M., Sorgenfrei, F., Giangrisostomi, E., Jay, R. M., Ovsyannikov, R., . . . Foehlisch, A. (2019). Directional sub-femtosecond charge transfer dynamics and the dimensionality of 1T-TaS2. Scientific Reports, 9, Article ID 488.
Open this publication in new window or tab >>Directional sub-femtosecond charge transfer dynamics and the dimensionality of 1T-TaS2
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2019 (English)In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 9, article id 488Article in journal (Refereed) Published
Abstract [en]

For the layered transition metal dichalcogenide 1T-TaS2, we establish through a unique experimental approach and density functional theory, how ultrafast charge transfer in 1T-TaS2 takes on isotropic three-dimensional character or anisotropic two-dimensional character, depending on the commensurability of the charge density wave phases of 1T-TaS2. The X-ray spectroscopic core-hole-clock method prepares selectively in-and out-of-plane polarized sulfur 3p orbital occupation with respect to the 1T-TaS2 planes and monitors sub-femtosecond wave packet delocalization. Despite being a prototypical two-dimensional material, isotropic three-dimensional charge transfer is found in the commensurate charge density wave phase (CCDW), indicating strong coupling between layers. In contrast, anisotropic two-dimensional charge transfer occurs for the nearly commensurate phase (NCDW). In direct comparison, theory shows that interlayer interaction in the CCDW phase - not layer stacking variations - causes isotropic three-dimensional charge transfer. This is presumably a general mechanism for phase transitions and tailored properties of dichalcogenides with charge density waves.

Place, publisher, year, edition, pages
NATURE PUBLISHING GROUP, 2019
National Category
Condensed Matter Physics
Identifiers
urn:nbn:se:uu:diva-376818 (URN)10.1038/s41598-018-36637-0 (DOI)000456553400054 ()30679501 (PubMedID)
Funder
EU, European Research Council, 669531 EDAXEU, European Research Council, 321319 ESUXEU, FP7, Seventh Framework Programme, 607232Carl Tryggers foundation
Available from: 2019-02-19 Created: 2019-02-19 Last updated: 2019-02-19Bibliographically approved
Jacobse, P. H., Simonov, K. A., Mangnus, M. J. J., Svirskiy, G. I., Generalov, A. V., Vinogradov, A. S., . . . Swart, I. (2019). One Precursor but Two Types of Graphene Nanoribbons: On-Surface Transformations of 10,10'-Dichloro-9,9'-bianthryl on Ag(111). The Journal of Physical Chemistry C, 123(14), 8892-8901
Open this publication in new window or tab >>One Precursor but Two Types of Graphene Nanoribbons: On-Surface Transformations of 10,10'-Dichloro-9,9'-bianthryl on Ag(111)
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2019 (English)In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 123, no 14, p. 8892-8901Article in journal (Refereed) Published
Abstract [en]

On-surface synthesis has emerged in the last decade as a method to create graphene nanoribbons (GNRs) with atomic precision. The underlying premise of this bottom-up strategy is that precursor molecules undergo a well-defined sequence of inter- and intramolecular reactions, leading to the formation of a single product. As such, the structure of the GNR is encoded in the precursors. However, recent examples have shown that not only the molecule, but also the coinage metal surface on which the reaction takes place, plays a decisive role in dictating the nanoribbon structure. In this work, we use scanning probe microscopy and X-ray photoelectron spectroscopy to investigate the behavior of 10,10'-dichloro-9,9'-bianthryl (DCBA) on Ag(111). Our study shows that Ag(111) can induce the formation of both seven-atom wide armchair GNRs (7-acGNRs) and 3,1-chiral GNRs (3,1-cGNRs), demonstrating that a single molecule on a single surface can react to different nanoribbon products. We additionally show that coadsorbed dibromoperylene can promote surface-assisted dehydrogenative coupling in DCBA, leading to the exclusive formation of 3,1-cGNRs.

National Category
Physical Chemistry
Identifiers
urn:nbn:se:uu:diva-382854 (URN)10.1021/acs.jpcc.8b12209 (DOI)000464768600048 ()31001369 (PubMedID)
Funder
Swedish Research CouncilSwedish Energy AgencyEU, FP7, Seventh Framework Programme, 321319Knut and Alice Wallenberg FoundationCarl Tryggers foundation
Available from: 2019-05-15 Created: 2019-05-15 Last updated: 2019-05-15Bibliographically approved
Svensson, S., Siegbahn, H., Nordgren, J. & Mårtensson, N. (2018). Biographical item: "Prof. Carl Nordling 1931-2016 Obituary" in Journal Of Electron Spectroscopy And Related Phenomena, vol 224, Special Issue: SI, pp 107-108. , 224
Open this publication in new window or tab >>Biographical item: "Prof. Carl Nordling 1931-2016 Obituary" in Journal Of Electron Spectroscopy And Related Phenomena, vol 224, Special Issue: SI, pp 107-108
2018 (English)Other (Other (popular science, discussion, etc.))
Series
Journal of Electron Spectroscopy and Related Phenomena, ISSN 0368-2048, E-ISSN 1873-2526
National Category
Condensed Matter Physics
Identifiers
urn:nbn:se:uu:diva-357035 (URN)10.1016/j.elspec.2016.12.008 (DOI)000428825400017 ()
Note

Minnesord (Obituary)

Available from: 2018-08-10 Created: 2018-08-10 Last updated: 2018-08-10Bibliographically approved
Kuehn, D., Sorgenfrei, F., Giangrisostomi, E., Jay, R., Musazay, A., Ovsyannikov, R., . . . Foehlisch, A. (2018). Capabilities of Angle Resolved Time of Flight electron spectroscopy with the 60 degrees wide angle acceptance lens. Journal of Electron Spectroscopy and Related Phenomena, 224, 45-50
Open this publication in new window or tab >>Capabilities of Angle Resolved Time of Flight electron spectroscopy with the 60 degrees wide angle acceptance lens
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2018 (English)In: Journal of Electron Spectroscopy and Related Phenomena, ISSN 0368-2048, E-ISSN 1873-2526, Vol. 224, p. 45-50Article in journal (Refereed) Published
Abstract [en]

The simultaneous detection of energy, momentum and temporal information in electron spectroscopy is the key aspect to enhance the detection efficiency in order to broaden the range of scientific applications. Employing a novel 60 degrees wide angle acceptance lens system, based on an additional accelerating electron optical element, leads to a significant enhancement in transmission over the previously employed 30 degrees electron lenses. Due to the performance gain, optimized capabilities for time resolved electron spectroscopy and other high transmission applications with pulsed ionizing radiation have been obtained. The energy resolution and transmission have been determined experimentally utilizing BESSY II as a photon source. Four different and complementary lens modes have been characterized. (C) 2017 The Authors. Published by Elsevier B.V.

Place, publisher, year, edition, pages
Elsevier, 2018
Keywords
Artof, Electron spectroscopy, Wide angle, Time of flight, Energy resolution, Synchrotron
National Category
Condensed Matter Physics
Identifiers
urn:nbn:se:uu:diva-351685 (URN)10.1016/j.elspec.2017.06.008 (DOI)000428825400009 ()
Funder
Swedish Research CouncilEU, FP7, Seventh Framework Programme, 321319Carl Tryggers foundation EU, Horizon 2020, 669531 EDAX
Available from: 2018-06-04 Created: 2018-06-04 Last updated: 2018-06-04Bibliographically approved
Giangrisostomi, E., Ovsyannikov, R., Sorgenfrei, F., Zhang, T., Lindblad, A., Sassa, Y., . . . Foehlisch, A. (2018). Low Dose Photoelectron Spectroscopy at BESSY II: Electronic structure of matter in its native state. Journal of Electron Spectroscopy and Related Phenomena, 224, 68-78
Open this publication in new window or tab >>Low Dose Photoelectron Spectroscopy at BESSY II: Electronic structure of matter in its native state
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2018 (English)In: Journal of Electron Spectroscopy and Related Phenomena, ISSN 0368-2048, E-ISSN 1873-2526, Vol. 224, p. 68-78Article in journal (Refereed) Published
Abstract [en]

The implementation of a high-transmission, angular-resolved time-of-Right electron spectrometer with a 1.25 MHz pulse selector at the PM4 soft X-ray dipole beamline of the synchrotron BESSY II creates unique capabilities to inquire electronic structure via photoelectron spectroscopy with a minimum of radiation dose. Solid-state samples can be prepared and characterized with standard UHV techniques and rapidly transferred from various preparation chambers to a 4-axis temperature-controlled measurement stage. A synchronized MHz laser system enables excited-state characterization and dynamical studies starting from the picosecond timescale. This article introduces the principal characteristics of the PM4 beamline and LowDosePES end-station. Recent results from graphene, an organic hole transport material for solar cells and the transition metal dichalcogenide MoS2 are presented to demonstrate the instrument performances. (C) 2017 The Authors. Published by Elsevier B.V.

Place, publisher, year, edition, pages
Elsevier, 2018
National Category
Atom and Molecular Physics and Optics
Identifiers
urn:nbn:se:uu:diva-351686 (URN)10.1016/j.elspec.2017.05.011 (DOI)000428825400012 ()
Funder
Swedish Research Council, 2014-6463EU, FP7, Seventh Framework Programme, 321319
Available from: 2018-06-04 Created: 2018-06-04 Last updated: 2018-06-04Bibliographically approved
Simonov, K., Generalov, A. V., Vinogradov, A. S., Svirskiy, G. I., Cafolla, A. A., McGuinness, C., . . . Preobrajenski, A. B. (2018). Synthesis of armchair graphene nanoribbons from the 10,10 '-dibromo-9,9 '-bianthracene molecules on Ag(111): the role of organometallic intermediates. Scientific Reports, 8, Article ID 3506.
Open this publication in new window or tab >>Synthesis of armchair graphene nanoribbons from the 10,10 '-dibromo-9,9 '-bianthracene molecules on Ag(111): the role of organometallic intermediates
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2018 (English)In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 8, article id 3506Article in journal (Refereed) Published
Abstract [en]

We investigate the bottom-up growth of N = 7 armchair graphene nanoribbons (7-AGNRs) from the 10,10'-dibromo-9,9'-bianthracene (DBBA) molecules on Ag(111) with the focus on the role of the organometallic (OM) intermediates. It is demonstrated that DBBA molecules on Ag(111) are partially debrominated at room temperature and lose all bromine atoms at elevated temperatures. Similar to DBBA on Cu(111), debrominated molecules form OM chains on Ag(111). Nevertheless, in contrast with the Cu(111) substrate, formation of polyanthracene chains from OM intermediates via an Ullmann-type reaction is feasible on Ag(111). Cleavage of C-Ag bonds occurs before the thermal threshold for the surface-catalyzed activation of C-H bonds on Ag(111) is reached, while on Cu(111) activation of C-H bonds occurs in parallel with the cleavage of the stronger C-Cu bonds. Consequently, while OM intermediates obstruct the Ullmann reaction between DBBA molecules on the Cu(111) substrate, they are required for the formation of polyanthracene chains on Ag(111). If the Ullmann-type reaction on Ag(111) is inhibited, heating of the OM chains produces nanographenes instead. Heating of the polyanthracene chains produces 7-AGNRs, while heating of nanographenes causes the formation of the disordered structures with the possible admixture of short GNRs.

Place, publisher, year, edition, pages
NATURE PUBLISHING GROUP, 2018
National Category
Physical Chemistry
Identifiers
urn:nbn:se:uu:diva-349343 (URN)10.1038/s41598-018-21704-3 (DOI)000425728600062 ()29472611 (PubMedID)
Funder
Swedish Research CouncilSwedish Energy AgencyEU, FP7, Seventh Framework Programme, 321319Knut and Alice Wallenberg Foundation
Available from: 2018-04-26 Created: 2018-04-26 Last updated: 2018-04-26Bibliographically approved
Mårtensson, N. & Eriksson, M. (2018). The saga of MAX IV, the first multi-bend achromat synchrotron light source. Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 907, 97-104
Open this publication in new window or tab >>The saga of MAX IV, the first multi-bend achromat synchrotron light source
2018 (English)In: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, ISSN 0168-9002, E-ISSN 1872-9576, Vol. 907, p. 97-104Article, review/survey (Refereed) Published
Abstract [en]

This paper describes how MAX IV, the first Multi-Bend Achromat (MBA) Synchrotron Radiation Light Source, was developed and realized. It describes the process of defining the scientific case and the development of the accelerator concepts. This was a highly interactive and intense optimization process, which went on during a long time with tight communication between the laboratory and the various user communities as well as with the funding agencies.

National Category
Accelerator Physics and Instrumentation
Identifiers
urn:nbn:se:uu:diva-366382 (URN)10.1016/j.nima.2018.03.018 (DOI)000444857200010 ()
Available from: 2018-11-21 Created: 2018-11-21 Last updated: 2018-11-21Bibliographically approved
Cappel, U. B., Svanström, S., Lanzilotto, V., Johansson, F. O. L., Aitola, K., Philippe, B., . . . Rensmo, H. (2017). Partially Reversible Photoinduced Chemical Changes in a Mixed-Ion Perovskite Material for Solar Cells. ACS Applied Materials and Interfaces, 9(40), 34970-34978
Open this publication in new window or tab >>Partially Reversible Photoinduced Chemical Changes in a Mixed-Ion Perovskite Material for Solar Cells
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2017 (English)In: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 9, no 40, p. 34970-34978Article in journal (Refereed) Published
Abstract [en]

Metal halide perovskites have emerged as materials of high interest for solar energy-to-electricity conversion, and in particular, the use of mixed-ion structures has led to high power conversion efficiencies and improved stability. For this reason, it is important to develop means to obtain atomic level understanding of the photoinduced behavior of these materials including processes such as photoinduced phase separation and ion migration. In this paper, we implement a new methodology combining visible laser illumination of a mixed-ion perovskite ((FAP-bI(3))(0.85)(MAPbBr(3))(0.15)) with the element specificity and chemical sensitivity of core-level photoelectron spectroscopy. By carrying out measurements at a synchrotron beamline optimized for low X-ray fluxes, we are able to avoid sample changes due to X-ray illumination and are therefore able to monitor what sample changes are induced by visible illumination only. We find that laser illumination causes partially reversible chemistry in the surface region, including enrichment of bromide at the surface, which could be related to a phase separation into bromide- and iodide-rich phases. We also observe a partially reversible formation of metallic lead in the perovskite structure. These processes occur on the time scale of minutes during illumination. The presented methodology has a large potential for understanding light-induced chemistry in photoactive materials and could specifically be extended to systematically study the impact of morphology and composition on the photostability of metal halide perovskites.

Place, publisher, year, edition, pages
AMER CHEMICAL SOC, 2017
Keywords
photoelectron spectroscopy, laser illumination, lead halide perovskite, ion migration, phase separation, stability
National Category
Condensed Matter Physics
Identifiers
urn:nbn:se:uu:diva-340141 (URN)10.1021/acsami.7b10643 (DOI)000413131500043 ()28925263 (PubMedID)
Funder
EU, FP7, Seventh Framework Programme, 321319Swedish Research Council, 2014-6019Swedish Research Council, 2014-6463StandUpSwedish Foundation for Strategic Research , RMA15-0130
Available from: 2018-01-26 Created: 2018-01-26 Last updated: 2018-01-26Bibliographically approved
Senkovskiy, B. V., Fedorov, A. V., Haberer, D., Farjam, M., Simonov, K. A., Preobrajenski, A. B., . . . Grueneis, A. (2017). Semiconductor-to-Metal Transition and Quasiparticle Renormalization in Doped Graphene Nanoribbons. ADVANCED ELECTRONIC MATERIALS, 3(4), Article ID 1600490.
Open this publication in new window or tab >>Semiconductor-to-Metal Transition and Quasiparticle Renormalization in Doped Graphene Nanoribbons
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2017 (English)In: ADVANCED ELECTRONIC MATERIALS, ISSN 2199-160X, Vol. 3, no 4, article id 1600490Article in journal (Refereed) Published
Abstract [en]

A semiconductor-to-metal transition in N = 7 armchair graphene nanoribbons causes drastic changes in its electron and phonon system. By using angle-resolved photoemission spectroscopy of lithium-doped graphene nanoribbons, a quasiparticle band gap renormalization from 2.4 to 2.1 eV is observed. Reaching high doping levels (0.05 electrons per atom), it is found that the effective mass of the conduction band carriers increases to a value equal to the free electron mass. This giant increase in the effective mass by doping is a means to enhance the density of states at the Fermi level which can have palpable impact on the transport and optical properties. Electron doping also reduces the Raman intensity by one order of magnitude, and results in relatively small (4 cm(-1)) hardening of the G phonon and softening of the D phonon. This suggests the importance of both lattice expansion and dynamic effects. The present work highlights that doping of a semiconducting 1D system is strikingly different from its 2D or 3D counterparts and introduces doped graphene nanoribbons as a new tunable quantum material with high potential for basic research and applications.

Place, publisher, year, edition, pages
WILEY, 2017
National Category
Materials Engineering
Identifiers
urn:nbn:se:uu:diva-322215 (URN)10.1002/aelm.201600490 (DOI)000399448600005 ()
Funder
EU, European Research Council, 648589 321319German Research Foundation (DFG), CRC1238 A1 GR 3708/2-1Swedish Research Council
Available from: 2017-05-17 Created: 2017-05-17 Last updated: 2017-05-22Bibliographically approved
Simonov, K. A., Vinogradov, N. A., Vinogradov, A. S., Generalov, A. V., Svirskiy, G. I., Cafolla, A. A., . . . Preobrajenski, A. B. (2016). Effect of Electron Injection in Copper-Contacted Graphene Nanoribbons. Nano Reseach, 9(9), 2735-2746
Open this publication in new window or tab >>Effect of Electron Injection in Copper-Contacted Graphene Nanoribbons
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2016 (English)In: Nano Reseach, ISSN 1998-0124, E-ISSN 1998-0000, Vol. 9, no 9, p. 2735-2746Article in journal (Refereed) Published
Abstract [en]

For practical electronic device applications of graphene nanoribbons (GNRs), it is essential to have abrupt and well-defined contacts between the ribbon and the adjacent metal lead. By analogy with graphene, these contacts can induce electron or hole doping, which may significantly affect the I/V characteristics of the device. Cu is among the most popular metals of choice for contact materials. In this study, we investigate the effect of in situ intercalation of Cu on the electronic structure of atomically precise, spatially aligned armchair GNRs of width N = 7 (7-AGNRs) fabricated via a bottom-up method on the Au(788) surface. Scanning tunneling microscopy data reveal that the complete intercalation of about one monolayer of Cu under 7-AGNRs can be facilitated by gentle annealing of the sample at 80 A degrees C. Angle-resolved photoemission spectroscopy (ARPES) data clearly reflect the one-dimensional character of the 7-AGNR band dispersion before and after intercalation. Moreover, ARPES and core-level photoemission results show that intercalation of Cu leads to significant electron injection into the nanoribbons, which causes a pronounced downshift of the valence and conduction bands of the GNR with respect to the Fermi energy (Delta E similar to 0.5 eV). As demonstrated by ARPES and X-ray absorption spectroscopy measurements, the effect of Cu intercalation is restricted to n-doping only, without considerable modification of the band structure of the GNRs. Post-annealing of the 7-AGNRs/Cu/Au(788) system at 200 A degrees C activates the diffusion of Cu into Au and the formation of a Cu-rich surface Au layer. Alloying of intercalated Cu leads to the recovery of the initial position of GNR-related bands with respect to the Fermi energy (E (F)), thus, proving the tunability of the induced n-doping.

Keywords
graphene nanoribbons, bottom-up method, copper intercalation, charge injection, ARPES, Scanning tunneling microscopy
National Category
Condensed Matter Physics Atom and Molecular Physics and Optics
Research subject
Physics with spec. in Atomic, Molecular and Condensed Matter Physics
Identifiers
urn:nbn:se:uu:diva-295867 (URN)10.1007/s12274-016-1162-2 (DOI)000382882200023 ()
Funder
Swedish Energy AgencySwedish Research CouncilEU, European Research Council, 321319Knut and Alice Wallenberg Foundation
Available from: 2016-06-10 Created: 2016-06-10 Last updated: 2017-11-28Bibliographically approved
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