Oxygen vacancy diffusion in bulk SrTiO3 from density functional theory calculations
Point defects and point defect diffusion contribute significantly to the properties of perovskite materials. However, even for the prototypical case of oxygen vacancies in SrTiO _{3} (STO), predictions vary widely. Here we present a comprehensive and systematic study of the diffusion barriers for this material. We use density functional theory (DFT) and assess the role of different cell sizes, density functionals, and charge states. Our results show that vacancyinduced octahedral rotations, which are limited by the boundary conditions of the supercell, can significantly affect the computed oxygen vacancy diffusion energy barrier. The diffusion energy barrier of a charged oxygen vacancy is lower than that of a neutral one. Unexpectedly, we find that with increasing supercell size, the effects of the oxygen vacancy charge state, the type of DFT exchange and correlation functional on the energy barrier diminish, and the different DFT predictions asymptote to a value in the range of 0.390.49 eV. This work provides important insight and guidance that should be considered for investigations of point defect diffusion in other perovskite materials and in oxide superlattices.
 Authors:

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 Univ. of Tennessee, Knoxville, TN (United States). Dept. of Material Science and Engineering
 Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Center for Nanophase Materials Science (CNMS)
 Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Center for Nanophase Materials Science (CNMS); Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Computer Science and Mathematics Division
 Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Materials Science and Technology Division
 Publication Date:
 Grant/Contract Number:
 AC0500OR22725; AC0205CH11231; UTTENN0112
 Type:
 Accepted Manuscript
 Journal Name:
 Computational Materials Science
 Additional Journal Information:
 Journal Volume: 118; Journal Issue: C; Journal ID: ISSN 09270256
 Publisher:
 Elsevier
 Research Org:
 Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
 Sponsoring Org:
 USDOE Laboratory Directed Research and Development (LDRD) Program; USDOE Office of Science (SC)
 Country of Publication:
 United States
 Language:
 English
 Subject:
 36 MATERIALS SCIENCE; DFT method; Perovskite structure; Oxygen vacancy; Diffusion energy barrier; Boundary condition
 OSTI Identifier:
 1334419
 Alternate Identifier(s):
 OSTI ID: 1341112
Zhang, Lipeng, Liu, Bin, Zhuang, Houlong, Kent, Paul R. C., Cooper, Valentino R., Ganesh, Panchapakesan, and Xu, Haixuan. Oxygen vacancy diffusion in bulk SrTiO3 from density functional theory calculations. United States: N. p.,
Web. doi:10.1016/j.commatsci.2016.02.041.
Zhang, Lipeng, Liu, Bin, Zhuang, Houlong, Kent, Paul R. C., Cooper, Valentino R., Ganesh, Panchapakesan, & Xu, Haixuan. Oxygen vacancy diffusion in bulk SrTiO3 from density functional theory calculations. United States. doi:10.1016/j.commatsci.2016.02.041.
Zhang, Lipeng, Liu, Bin, Zhuang, Houlong, Kent, Paul R. C., Cooper, Valentino R., Ganesh, Panchapakesan, and Xu, Haixuan. 2016.
"Oxygen vacancy diffusion in bulk SrTiO3 from density functional theory calculations". United States.
doi:10.1016/j.commatsci.2016.02.041. https://www.osti.gov/servlets/purl/1334419.
@article{osti_1334419,
title = {Oxygen vacancy diffusion in bulk SrTiO3 from density functional theory calculations},
author = {Zhang, Lipeng and Liu, Bin and Zhuang, Houlong and Kent, Paul R. C. and Cooper, Valentino R. and Ganesh, Panchapakesan and Xu, Haixuan},
abstractNote = {Point defects and point defect diffusion contribute significantly to the properties of perovskite materials. However, even for the prototypical case of oxygen vacancies in SrTiO3 (STO), predictions vary widely. Here we present a comprehensive and systematic study of the diffusion barriers for this material. We use density functional theory (DFT) and assess the role of different cell sizes, density functionals, and charge states. Our results show that vacancyinduced octahedral rotations, which are limited by the boundary conditions of the supercell, can significantly affect the computed oxygen vacancy diffusion energy barrier. The diffusion energy barrier of a charged oxygen vacancy is lower than that of a neutral one. Unexpectedly, we find that with increasing supercell size, the effects of the oxygen vacancy charge state, the type of DFT exchange and correlation functional on the energy barrier diminish, and the different DFT predictions asymptote to a value in the range of 0.390.49 eV. This work provides important insight and guidance that should be considered for investigations of point defect diffusion in other perovskite materials and in oxide superlattices.},
doi = {10.1016/j.commatsci.2016.02.041},
journal = {Computational Materials Science},
number = C,
volume = 118,
place = {United States},
year = {2016},
month = {4}
}