Depth-Resolved Composition and Electronic Structure of Buried Layers and Interfaces in a LaNiO3/SrTiO3 Superlatticefroni Soft- and Hard-X-ray Standing-Wave Angle-Resolved Photoemission
2016 (English)In: Journal of Electron Spectroscopy and Related Phenomena, ISSN 0368-2048, E-ISSN 1873-2526, Vol. 211, 70-81 p.Article in journal (Refereed) Published
Univ Calif Davis, Dept Phys, Davis, CA 95616 USA.;Lawrence Berkeley Natl Lab, Div Mat Sci, Berkeley, CA 94720 USA..
Pálsson, Gunna K.
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Physics. Univ Calif Davis, Dept Phys, Davis, CA 95616 USA.;Lawrence Berkeley Natl Lab, Div Mat Sci, Berkeley, CA 94720 USA..
Univ Calif Davis, Dept Phys, Davis, CA 95616 USA.;Lawrence Berkeley Natl Lab, Div Mat Sci, Berkeley, CA 94720 USA.;Forschungszentrum Julich, Peter Grunberg Inst PGI 6, D-52425 Julich, Germany..
Gray, A. X.
Univ Calif Davis, Dept Phys, Davis, CA 95616 USA.;Lawrence Berkeley Natl Lab, Div Mat Sci, Berkeley, CA 94720 USA.;SLAC Natl Accelerator Lab, Stanford Inst Mat & Energy Sci, Menlo Pk, CA 94025 USA.;Temple Univ, Dept Phys, Philadelphia, PA 19122 USA..
LaNiO3 (LNO) is an intriguing member of the rare-earth nickelates in exhibiting a metal-insulator transition for a critical film thickness of about 4 unit cells [Son et al., Appl. Phys. Lett. 96, 062114 (2010)]; however, such thin films also show a transition to a metallic state in superlattices with SrTiO3 (STO) [Son et al., Appl. Phys. Lett. 97, 202109 (2010)]. In order to better understand this transition, we have studied a strained LNO/STO superlattice with 10 repeats of [4 unit-cell LNO/3 unit-cell STO] grown on an (LaAlO3)(0.3)(Sr2AlTaO6)(0.7) substrate using soft x-ray standing-wave-excited angle-resolved photoemission (SWARPES), together with soft- and hard- x-ray photoemission-measurements of core levels and densities-of-states valence spectra. The experimental results are compared with state-of-the-art density functional theory (DFT) calculations of band structures and densities of states. Using core-level rocking curves and x-ray optical modeling to assess the position of the standing wave, SWARPES measurements are carried out for various incidence angles and used to determine interface-specific changes in momentum-resolved electronic structure. We further show that the momentum-resolved behavior of the Ni 3d e(g) and t(2g) states near the Fermi level, as well as those at the bottom of the valence bands, is very similar to recently published SWARPES results for a related La0.7Sr0.3MnO3/SrTiO3 superlattice that was-studied using the same technique (Gray et al., Europhysics Letters 104, 17004 (2013)), which further validates this experimental approach and our conclusions. Our conclusions are also supported in several ways by comparison to DFT calculations for the parent materials and the superlattice, including layer-resolved density-of-states results.
Place, publisher, year, edition, pages
2016. Vol. 211, 70-81 p.
Atom and Molecular Physics and Optics
IdentifiersURN: urn:nbn:se:uu:diva-304430DOI: 10.1016/j.elspec.2016.04.008ISI: 000382343100009OAI: oai:DiVA.org:uu-304430DiVA: diva2:1033132
FunderSwedish Research CouncilGerman Research Foundation (DFG), SFB/TR80