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First-principles thermodynamic modeling of lanthanum chromate perovskites

Dalach, P. and Ellis, D. E. and van de Walle, A. (2012) First-principles thermodynamic modeling of lanthanum chromate perovskites. Physical Review B, 85 (1). 014108. ISSN 1098-0121. doi:10.1103/PhysRevB.85.014108. https://resolver.caltech.edu/CaltechAUTHORS:20120210-100303735

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Abstract

Tendencies toward local atomic ordering in (A,A′)(B,B′)O_(3−δ) mixed composition perovskites are modeled to explore their influence on thermodynamic, transport, and electronic properties. In particular, dopants and defects within lanthanum chromate perovskites are studied under various simulated redox environments. (La_(1−x),Sr_x)(Cr_(1−y),Fe_y)O_(3−δ) (LSCF) and (La_(1−x),Sr_x)(Cr_(1−y),Ru_y)O_(3−δ) (LSCR) are modeled using a cluster expansion statistical thermodynamics method built upon a density functional theory database of structural energies. The cluster expansions are utilized in lattice Monte Carlo simulations to compute the ordering of Sr and Fe(Ru) dopant and oxygen vacancies (Vac). Reduction processes are modeled via the introduction of oxygen vacancies, effectively forcing excess electronic charge onto remaining atoms. LSCR shows increasingly extended Ru-Vac associates and short-range Ru-Ru and Ru-Vac interactions upon reduction; LSCF shows long-range Fe-Fe and Fe-Vac interaction ordering, inhibiting mobility. First principles density functional calculations suggest that Ru-Vac associates significantly decrease the activation energy of Ru-Cr swaps in reduced LSCR. These results are discussed in view of experimentally observed extrusion of metallic Ru from LSCR nanoparticles under reducing conditions at elevated temperature.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1103/PhysRevB.85.014108DOIUNSPECIFIED
http://link.aps.org/doi/10.1103/PhysRevB.85.014108PublisherUNSPECIFIED
ORCID:
AuthorORCID
van de Walle, A.0000-0002-3415-1494
Additional Information:© 2012 American Physical Society. Received 16 May 2011; revised 15 November 2011; published 17 January 2012. Work supported by the US Department of Energy, Basic Energy Sciences, under Award Number DE-FG02-05ER46255, by the US National Science Foundation under Grant DMR-0953378 and by Teragrid Resources provided by NCSA under Grant No. DMR050013N.
Funders:
Funding AgencyGrant Number
Department of Energy (DOE) Basic Energy SciencesDE-FG02-05ER46255
NSFDMR-0953378
NCSA Teragrid ResourcesDMR050013N
Issue or Number:1
Classification Code:PACS: 61.72.Bb, 61.72.J-, 66.10.Ed
DOI:10.1103/PhysRevB.85.014108
Record Number:CaltechAUTHORS:20120210-100303735
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20120210-100303735
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:29234
Collection:CaltechAUTHORS
Deposited By: Jason Perez
Deposited On:10 Feb 2012 22:29
Last Modified:09 Nov 2021 17:05

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