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Title: Composition dependent intrinsic defect structures in SrTiO3

Abstract

Intrinsic point defect complexes in SrTiO3 under different chemical conditions are studied using density functional theory. The Schottky defect complex consisting of nominally charged Sr, Ti and O vacancies is predicted to be the most stable defect structure in stoichiometric SrTiO3, with a relatively low formation energy of 1.64 eV/defect. In addition, the mechanisms of defect complex formation in nonstoichiometric SrTiO3 are investigated. Excess SrO leads to the formation of the oxygen vacancies and a strontium-titanium antisite defect, while a strontium vacancy together with an oxygen vacancy and the titanium-strontium antisite defect are produced in an excess TiO2 environment. Since point defects, such as oxygen vacancies and cation antisite defects, are intimately related to the functionality of SrTiO3, these results provide guidelines for controlling the formation of intrinsic point defects and optimizing the functionality of SrTiO3 by controlling nonstoichiometric chemical compositions of SrO and TiO2 in experiments.

Authors:
 [1];  [1];  [2];  [2];  [1];  [1]
  1. ORNL
  2. University of Tennessee, Knoxville (UTK)
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
1147714
DOE Contract Number:
DE-AC05-00OR22725
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Chemistry Chemical Physics; Journal Volume: 16; Journal Issue: 29
Country of Publication:
United States
Language:
English
Subject:
Strontium titanate; defects; density functional theory

Citation Formats

Liu, Bin, Cooper, Valentino R, Xu, Haixuan, Xiao, Haiyan, Zhang, Yanwen, and Weber, William J. Composition dependent intrinsic defect structures in SrTiO3. United States: N. p., 2014. Web. doi:10.1039/c4cp01510j.
Liu, Bin, Cooper, Valentino R, Xu, Haixuan, Xiao, Haiyan, Zhang, Yanwen, & Weber, William J. Composition dependent intrinsic defect structures in SrTiO3. United States. doi:10.1039/c4cp01510j.
Liu, Bin, Cooper, Valentino R, Xu, Haixuan, Xiao, Haiyan, Zhang, Yanwen, and Weber, William J. 2014. "Composition dependent intrinsic defect structures in SrTiO3". United States. doi:10.1039/c4cp01510j.
@article{osti_1147714,
title = {Composition dependent intrinsic defect structures in SrTiO3},
author = {Liu, Bin and Cooper, Valentino R and Xu, Haixuan and Xiao, Haiyan and Zhang, Yanwen and Weber, William J},
abstractNote = {Intrinsic point defect complexes in SrTiO3 under different chemical conditions are studied using density functional theory. The Schottky defect complex consisting of nominally charged Sr, Ti and O vacancies is predicted to be the most stable defect structure in stoichiometric SrTiO3, with a relatively low formation energy of 1.64 eV/defect. In addition, the mechanisms of defect complex formation in nonstoichiometric SrTiO3 are investigated. Excess SrO leads to the formation of the oxygen vacancies and a strontium-titanium antisite defect, while a strontium vacancy together with an oxygen vacancy and the titanium-strontium antisite defect are produced in an excess TiO2 environment. Since point defects, such as oxygen vacancies and cation antisite defects, are intimately related to the functionality of SrTiO3, these results provide guidelines for controlling the formation of intrinsic point defects and optimizing the functionality of SrTiO3 by controlling nonstoichiometric chemical compositions of SrO and TiO2 in experiments.},
doi = {10.1039/c4cp01510j},
journal = {Physical Chemistry Chemical Physics},
number = 29,
volume = 16,
place = {United States},
year = 2014,
month = 1
}
  • Low-energy-electron diffraction, Auger-electron spectroscopy, electron-energy-loss, and ultraviolet-photoelectron spectroscopies were used to study the structure, composition, and electron energy distribution of a clean single-crystal (111) face of strontium titanate (perovskite). The dependence of the surface chemical composition on the temperature has been observed along with corresponding changes in the surface electronic properties. High-temperature Ar-ion bombardment causes an irreversible change in the surface structure, stoichiometry, and electron energy distribution. In contrast to the TiO{sub 2} surface, there are always significant concentrations of Ti{sup 3+} in an annealed ordered SrTiO{sub 3} (111) surface. This stable active Ti{sup 3+} monolayer on top of amore » substrate with large surface dipole potential makes SrTiO{sub 3} superior to TiO{sub 2} when used as a photoanode in the photoelectrochemical cell.« less
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