Charge compensation and electrostatic transferability in three entropy-stabilized oxides

Results from density functional theory calculations

Zs Rak, C. M. Rost, M. Lim, P. Sarker, C. Toher, S. Curtarolo, Jon-Paul Maria, D. W. Brenner

Research output: Contribution to journalArticle

30 Citations (Scopus)

Abstract

Density functional theory calculations were carried out for three entropic rocksalt oxides, (Mg 0.1 Co 0.1 Ni 0.1 Cu 0.1 Zn 0.1 )O 0.5 , termed J14, and J14 + Li and J14 + Sc, to understand the role of charge neutrality and electronic states on their properties, and to probe whether simple expressions may exist that predict stability. The calculations predict that the average lattice constants of the ternary structures provide good approximations to that of the random structures. For J14, Bader charges are transferable between the binary, ternary, and random structures. For J14 + Sc and J14 + Li, average Bader charges in the entropic structures can be estimated from the ternary compositions. Addition of Sc to J14 reduces the majority of Cu, which show large displacements from ideal lattice sites, along with reduction of a few Co and Ni cations. Addition of Li to J14 reduces the lattice constant, consistent with experiment, and oxidizes some of Co as well as some of Ni and Cu. The Bader charges and spin-resolved density of states (DOS) for Co +3 in J14 + Li are very different from Co +2 , while for Cu and Ni the Bader charges form continuous distributions and the two DOS are similar for the two oxidation states. Experimental detection of different oxidation states may therefore be challenging for Cu and Ni compared to Co. Based on these results, empirical stability parameters for these entropic oxides may be more complicated than those for non-oxide entropic solids.

Original languageEnglish (US)
Article number095105
JournalJournal of Applied Physics
Volume120
Issue number9
DOIs
StatePublished - Sep 7 2016

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entropy
electrostatics
density functional theory
oxides
oxidation
cations
probes
approximation
electronics

All Science Journal Classification (ASJC) codes

  • Physics and Astronomy(all)

Cite this

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title = "Charge compensation and electrostatic transferability in three entropy-stabilized oxides: Results from density functional theory calculations",
abstract = "Density functional theory calculations were carried out for three entropic rocksalt oxides, (Mg 0.1 Co 0.1 Ni 0.1 Cu 0.1 Zn 0.1 )O 0.5 , termed J14, and J14 + Li and J14 + Sc, to understand the role of charge neutrality and electronic states on their properties, and to probe whether simple expressions may exist that predict stability. The calculations predict that the average lattice constants of the ternary structures provide good approximations to that of the random structures. For J14, Bader charges are transferable between the binary, ternary, and random structures. For J14 + Sc and J14 + Li, average Bader charges in the entropic structures can be estimated from the ternary compositions. Addition of Sc to J14 reduces the majority of Cu, which show large displacements from ideal lattice sites, along with reduction of a few Co and Ni cations. Addition of Li to J14 reduces the lattice constant, consistent with experiment, and oxidizes some of Co as well as some of Ni and Cu. The Bader charges and spin-resolved density of states (DOS) for Co +3 in J14 + Li are very different from Co +2 , while for Cu and Ni the Bader charges form continuous distributions and the two DOS are similar for the two oxidation states. Experimental detection of different oxidation states may therefore be challenging for Cu and Ni compared to Co. Based on these results, empirical stability parameters for these entropic oxides may be more complicated than those for non-oxide entropic solids.",
author = "Zs Rak and Rost, {C. M.} and M. Lim and P. Sarker and C. Toher and S. Curtarolo and Jon-Paul Maria and Brenner, {D. W.}",
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Charge compensation and electrostatic transferability in three entropy-stabilized oxides : Results from density functional theory calculations. / Rak, Zs; Rost, C. M.; Lim, M.; Sarker, P.; Toher, C.; Curtarolo, S.; Maria, Jon-Paul; Brenner, D. W.

In: Journal of Applied Physics, Vol. 120, No. 9, 095105, 07.09.2016.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Charge compensation and electrostatic transferability in three entropy-stabilized oxides

T2 - Results from density functional theory calculations

AU - Rak, Zs

AU - Rost, C. M.

AU - Lim, M.

AU - Sarker, P.

AU - Toher, C.

AU - Curtarolo, S.

AU - Maria, Jon-Paul

AU - Brenner, D. W.

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Y1 - 2016/9/7

N2 - Density functional theory calculations were carried out for three entropic rocksalt oxides, (Mg 0.1 Co 0.1 Ni 0.1 Cu 0.1 Zn 0.1 )O 0.5 , termed J14, and J14 + Li and J14 + Sc, to understand the role of charge neutrality and electronic states on their properties, and to probe whether simple expressions may exist that predict stability. The calculations predict that the average lattice constants of the ternary structures provide good approximations to that of the random structures. For J14, Bader charges are transferable between the binary, ternary, and random structures. For J14 + Sc and J14 + Li, average Bader charges in the entropic structures can be estimated from the ternary compositions. Addition of Sc to J14 reduces the majority of Cu, which show large displacements from ideal lattice sites, along with reduction of a few Co and Ni cations. Addition of Li to J14 reduces the lattice constant, consistent with experiment, and oxidizes some of Co as well as some of Ni and Cu. The Bader charges and spin-resolved density of states (DOS) for Co +3 in J14 + Li are very different from Co +2 , while for Cu and Ni the Bader charges form continuous distributions and the two DOS are similar for the two oxidation states. Experimental detection of different oxidation states may therefore be challenging for Cu and Ni compared to Co. Based on these results, empirical stability parameters for these entropic oxides may be more complicated than those for non-oxide entropic solids.

AB - Density functional theory calculations were carried out for three entropic rocksalt oxides, (Mg 0.1 Co 0.1 Ni 0.1 Cu 0.1 Zn 0.1 )O 0.5 , termed J14, and J14 + Li and J14 + Sc, to understand the role of charge neutrality and electronic states on their properties, and to probe whether simple expressions may exist that predict stability. The calculations predict that the average lattice constants of the ternary structures provide good approximations to that of the random structures. For J14, Bader charges are transferable between the binary, ternary, and random structures. For J14 + Sc and J14 + Li, average Bader charges in the entropic structures can be estimated from the ternary compositions. Addition of Sc to J14 reduces the majority of Cu, which show large displacements from ideal lattice sites, along with reduction of a few Co and Ni cations. Addition of Li to J14 reduces the lattice constant, consistent with experiment, and oxidizes some of Co as well as some of Ni and Cu. The Bader charges and spin-resolved density of states (DOS) for Co +3 in J14 + Li are very different from Co +2 , while for Cu and Ni the Bader charges form continuous distributions and the two DOS are similar for the two oxidation states. Experimental detection of different oxidation states may therefore be challenging for Cu and Ni compared to Co. Based on these results, empirical stability parameters for these entropic oxides may be more complicated than those for non-oxide entropic solids.

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