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Title: Symmetry-dependent interfacial reconstruction to compensate polar discontinuity at perovskite oxide interfaces (LaAlO{sub 3}/SrTiO{sub 3} and LaAlO{sub 3}/CaTiO{sub 3})

We report the crystal symmetry-dependency of the interfacial reconstruction to relieve the polar discontinuity at the complex oxide heterointerfaces. We chose LaAlO{sub 3}/SrTiO{sub 3} and LaAlO{sub 3}/CaTiO{sub 3} interfaces as model systems, where the neutral TiO{sub 2} and the positive LaO{sup +} layers form the polar discontinuity at the interface with TiO{sub 2}-terminated (001) cubic SrTiO{sub 3} and orthorhombic CaTiO{sub 3}. Using scanning transmission electron microscopy, we observed that the interlayer distance abnormally increased at the interface. We performed the first-principles calculations to understand the detailed atomic displacement at the interfaces having no oxygen vacancy and intermixing. Our results show that cations were reconstructed in different ways depending on the crystal symmetry through the octahedral tilts and atomic displacements to compensate the polar discontinuity at the interfaces. Our results imply that the interfacial reconstructions have to be considered along with the ionic compensation (intermixing) and electronic compensation (two dimensional electron gas) to fully understand the interfacial phenomena.
Authors:
; ; ;  [1] ;  [2] ;  [1] ;  [3] ;  [4] ;  [1] ;  [3] ;  [2] ;  [3]
  1. Electronic Materials Research Center, Korea Institute of Science and Technology, Seoul 136-791 (Korea, Republic of)
  2. Advanced Analysis Center, Korea Institute of Science and Technology, Seoul 136-791 (Korea, Republic of)
  3. (Korea, Republic of)
  4. Department of Materials Science and Engineering and Inter-University Semiconductor Research Center, Seoul National University, Seoul 151-744 (Korea, Republic of)
Publication Date:
OSTI Identifier:
22412645
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 106; Journal Issue: 7; Other Information: (c) 2015 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; ALUMINATES; ATOMIC DISPLACEMENTS; CATIONS; CRYSTALS; ELECTRON GAS; INTERFACES; LANTHANUM OXIDES; LAYERS; ORTHORHOMBIC LATTICES; OXYGEN; PEROVSKITE; STRONTIUM TITANATES; SYMMETRY; TITANIUM OXIDES; TRANSMISSION ELECTRON MICROSCOPY; TWO-DIMENSIONAL SYSTEMS; VACANCIES