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Title: Interface energetics and atomic structure of epitaxial La{sub 1−x}Sr{sub x}CoO{sub 3} on Nb:SrTiO{sub 3}

The energetics at oxide semiconductor/La{sub 1−x}Sr{sub x}CoO{sub 3} heterojunctions, including the respective alignment of the valence and conduction bands, govern charge transfer and have to be determined for the design of future La{sub 1−x}Sr{sub x}CoO{sub 3}-based devices. In this letter, the electronic and atomic structures of epitaxial La{sub 1−x}Sr{sub x}CoO{sub 3} on Nb-doped strontium titanate are revealed by scanning transmission electron microscopy, electron energy loss spectroscopy, and in situ x-ray and ultra violet photoelectron spectroscopies. For LaCoO{sub 3}, a valence band (VB) offset of 2.8 ± 0.1 eV is deduced. The large offset is attributed to the orbital contributions of the Co 3d states to the VB maximum of the LaCoO{sub 3} thin films, with no evidence of interface dipole contributions. The sensitivity of the valence band orbital character to spin state ordering and oxygen vacancies is assessed using density functional theory.
Authors:
 [1] ; ; ; ; ;  [2] ;  [3] ; ; ;  [4]
  1. Institute of Mechanics, Materials and Civil Engineering, Université catholique de Louvain, B-1348 Louvain-la-Neuve (Belgium)
  2. Fujitsu Laboratories, Atsugi, Kanagawa-ken (Japan)
  3. Interdisciplinary Graduate School of Science and Engineering, Tokyo Institute of Technology, 4259-G2-25 Nagatsuta, Midori-ku, Yokohama 226–8502 (Japan)
  4. Graduate School of Engineering, Osaka Prefecture University, 1-1 Gakuen-cho, Naka-ku, Sakai, Osaka 599-8531 (Japan)
Publication Date:
OSTI Identifier:
22483063
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 106; Journal Issue: 24; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; DENSITY FUNCTIONAL METHOD; DOPED MATERIALS; ENERGY-LOSS SPECTROSCOPY; EPITAXY; INTERFACES; OXIDES; PHOTOELECTRON SPECTROSCOPY; SEMICONDUCTOR MATERIALS; SENSITIVITY; STRONTIUM TITANATES; THIN FILMS; TRANSMISSION ELECTRON MICROSCOPY; VACANCIES; X RADIATION