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Title: Band alignment of epitaxial SrTiO{sub 3} thin films with (LaAlO{sub 3}){sub 0.3}-(Sr{sub 2}AlTaO{sub 6}){sub 0.7} (001)

SrTiO{sub 3} (STO) epitaxial thin films and heterostructures are of considerable interest due to the wide range of functionalities they exhibit. The alloy perovskite (LaAlO{sub 3}){sub 0.3}-(Sr{sub 2}AlTaO{sub 6}){sub 0.7} (LSAT) is commonly used as a substrate for these material structures due to its structural compatibility with STO and the strain-induced ferroelectric response in STO films grown on LSAT. However, surprisingly little is known about the electronic properties of the STO/LSAT interface despite its potentially important role in affecting the overall electronic structure of system. We examine the band alignment of STO/LSAT heterostructures using x-ray photoelectron spectroscopy for epitaxial STO films deposited using two different molecular beam epitaxy approaches. We find that the valence band offset ranges from +0.2(1) eV to −0.2(1) eV depending on the film surface termination. From these results, we extract a conduction band offset from −2.4(1) eV to −2.8(1) eV, indicating that the conduction band edge is more deeply bound in STO and that LSAT will not act as a sink or trap for electrons in the supported film or multilayer.
Authors:
;  [1] ; ;  [2]
  1. Physical Sciences Division, Pacific Northwest National Laboratory, Richland, Washington 99352 (United States)
  2. Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, Minnesota 55455 (United States)
Publication Date:
OSTI Identifier:
22482162
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 107; Journal Issue: 13; 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; ALLOYS; ALUMINATES; DEPOSITS; ELECTRONIC STRUCTURE; FERROELECTRIC MATERIALS; INTERFACES; LANTHANUM COMPOUNDS; LAYERS; MOLECULAR BEAM EPITAXY; PEROVSKITE; POTENTIALS; SINKS; STRAINS; STRONTIUM TITANATES; SUBSTRATES; SURFACES; THIN FILMS; TRAPS; VALENCE; X-RAY PHOTOELECTRON SPECTROSCOPY