Diffusion quantum Monte Carlo calculations of SrFeO _{3} and LaFeO _{3}
The equations of state, formation energy, and migration energy barrier of the oxygen vacancy in SrFeO _{3} and LaFeO _{3} were calculated in this paper with the diffusion quantum Monte Carlo (DMC) method. Calculations were also performed with various Density Functional Theory (DFT) approximations for comparison. DMC reproduces the measured cohesive energies of these materials with errors below 0.23(5) eV and the structural properties within 1% of the experimental values. The DMC formation energies of the oxygen vacancy in SrFeO _{3} and LaFeO _{3} under oxygenrich conditions are 1.3(1) and 6.24(7) eV, respectively. Similar calculations with semilocal DFT approximations for LaFeO _{3} yielded vacancy formation energies 1.5 eV lower. Comparison of charge density evaluated with DMC and DFT approximations shows that DFT tends to overdelocalize the electrons in defected SrFeO _{3} and LaFeO _{3}. Finally, calculations with DMC and local density approximation yield similar vacancy migration energy barriers, indicating that steric/electrostatic effects mainly determine migration barriers in these materials.
 Authors:

^{[1]}
;
^{[2]};
^{[3]}
;
^{[2]}
 Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Materials Science and Technology Division; Univ. of Puerto Rico, Cayey, PR (United States). Dept. of Chemistry
 Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Materials Science and Technology Division
 Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Center for Nanophase Materials Sciences. Computer Science and Mathematics Division
 Publication Date:
 Grant/Contract Number:
 AC0500OR22725
 Type:
 Accepted Manuscript
 Journal Name:
 Journal of Chemical Physics
 Additional Journal Information:
 Journal Volume: 147; Journal Issue: 3; Journal ID: ISSN 00219606
 Publisher:
 American Institute of Physics (AIP)
 Research Org:
 Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
 Sponsoring Org:
 USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC22)
 Contributing Orgs:
 Univ. of Puerto Rico, Cayey, PR (United States)
 Country of Publication:
 United States
 Language:
 English
 Subject:
 37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; Chemical compounds; Monte Carlo methods; Density functional theory; Crystal defects; Intermolecular forces
 OSTI Identifier:
 1376467
 Alternate Identifier(s):
 OSTI ID: 1371601
Santana, Juan A., Krogel, Jaron T., Kent, Paul R. C., and Reboredo, Fernando A.. Diffusion quantum Monte Carlo calculations of SrFeO3 and LaFeO3. United States: N. p.,
Web. doi:10.1063/1.4994083.
Santana, Juan A., Krogel, Jaron T., Kent, Paul R. C., & Reboredo, Fernando A.. Diffusion quantum Monte Carlo calculations of SrFeO3 and LaFeO3. United States. doi:10.1063/1.4994083.
Santana, Juan A., Krogel, Jaron T., Kent, Paul R. C., and Reboredo, Fernando A.. 2017.
"Diffusion quantum Monte Carlo calculations of SrFeO3 and LaFeO3". United States.
doi:10.1063/1.4994083. https://www.osti.gov/servlets/purl/1376467.
@article{osti_1376467,
title = {Diffusion quantum Monte Carlo calculations of SrFeO3 and LaFeO3},
author = {Santana, Juan A. and Krogel, Jaron T. and Kent, Paul R. C. and Reboredo, Fernando A.},
abstractNote = {The equations of state, formation energy, and migration energy barrier of the oxygen vacancy in SrFeO3 and LaFeO3 were calculated in this paper with the diffusion quantum Monte Carlo (DMC) method. Calculations were also performed with various Density Functional Theory (DFT) approximations for comparison. DMC reproduces the measured cohesive energies of these materials with errors below 0.23(5) eV and the structural properties within 1% of the experimental values. The DMC formation energies of the oxygen vacancy in SrFeO3 and LaFeO3 under oxygenrich conditions are 1.3(1) and 6.24(7) eV, respectively. Similar calculations with semilocal DFT approximations for LaFeO3 yielded vacancy formation energies 1.5 eV lower. Comparison of charge density evaluated with DMC and DFT approximations shows that DFT tends to overdelocalize the electrons in defected SrFeO3 and LaFeO3. Finally, calculations with DMC and local density approximation yield similar vacancy migration energy barriers, indicating that steric/electrostatic effects mainly determine migration barriers in these materials.},
doi = {10.1063/1.4994083},
journal = {Journal of Chemical Physics},
number = 3,
volume = 147,
place = {United States},
year = {2017},
month = {7}
}
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