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Title: Revealing the atomic and electronic structure of a SrTiO{sub 3}/LaNiO{sub 3}/SrTiO{sub 3} heterostructure interface

The atomic structures of SrTiO{sub 3} (STO)/LaNiO{sub 3} (LNO)/STO heterostructure interfaces were investigated by spherical aberration-corrected (C{sub S}) (scanning) transmission electron microscopy. Atomic displacement and lattice distortion measurements and electron energy loss spectroscopy (EELS) were used to quantitatively analyze the distortion of the interfacial octahedra and the bond length at the interfaces. Combined with high-resolution transmission electron microscopy (HRTEM) and scanning transmission electron microscopy analyses, two distinct interfacial atomic terminating layers are unambiguously determined. Ensuing quantitative HRTEM measurements revealed that the Ni-O bond length in the interfacial octahedral is elongated at the bottom interface (–NiO{sub 2}-SrO–). Atomic displacement shows structural relaxation effects when crossing the interfaces and lattice distortions across the interface is more pronounced in LNO than in STO. The Ti/O atomic ratio, La and Ti relative atomic ratio as derived by EELS quantification indicate non-stoichiometric composition at the interfaces. Distinct fine structures of Ti-L{sub 2,3} edge and O-K edge at the bottom and top interfaces are observed. By comparison, we are able to estimate Ti valency at both interfaces. Combining the structural distortions and Ti valency, the polar discontinuity and charge transfer at the interfaces are discussed.
Authors:
 [1] ;  [2] ;  [3] ;  [4] ;  [5] ; ;  [3] ;  [6]
  1. Erich Schmid Institute of Materials Science, Austrian Academy of Sciences, Leoben (Austria)
  2. (Germany)
  3. Max-Planck Institute for Solid State Research, D-70561 Stuttgart (Germany)
  4. (Egypt)
  5. INM—Leibniz-Institut für Neue Materialien, 66123 Saarbrücken (Germany)
  6. Electron Microscopy Group for Materials Science, University of Ulm, Ulm (Germany)
Publication Date:
OSTI Identifier:
22277866
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 115; Journal Issue: 10; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; ATOMIC DISPLACEMENTS; BOND LENGTHS; COMPARATIVE EVALUATIONS; ELECTRONIC STRUCTURE; ELECTRONS; ENERGY-LOSS SPECTROSCOPY; FINE STRUCTURE; GEOMETRICAL ABERRATIONS; INTERFACES; LANTHANUM COMPOUNDS; LAYERS; NIOBATES; RELAXATION; STRONTIUM TITANATES; TRANSMISSION ELECTRON MICROSCOPY; VALENCE