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

Journal Article · Fri Mar 14 00:00:00 EDT 2014 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.4868513· OSTI ID:22277866

Zhang, Zaoli ^[1]; Soltan, S. ^[2]; Schmid, H. ^[3]; Habermeier, H. -U.; Keimer, B. ^[2]; Kaiser, U. ^[4]

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1. Erich Schmid Institute of Materials Science, Austrian Academy of Sciences, Leoben (Austria)
2. Max-Planck Institute for Solid State Research, D-70561 Stuttgart (Germany)
3. INM—Leibniz-Institut für Neue Materialien, 66123 Saarbrücken (Germany)
4. Electron Microscopy Group for Materials Science, University of Ulm, Ulm (Germany)

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.

• OSTI ID: 22277866
• Journal Information: Journal of Applied Physics, Vol. 115, Issue 10; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

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