Effect of \(A\)-site size difference on polar behavior in \(M\)BiScNbO\(_6\),($M$$=$Na, K and Rb): Density functional calculations

We investigate the effect of \(A\)-site size differences in the double perovskites BiScO\(_3\)-\(M\)NbO\(_3\) ($M$$=\(Na, K and Rb) using first-principles calculations. We find that the polarization of these materials is 70\)\sim\(90 \)\mu\(C/cm\)^2\( along the rhombohedral direction. The main contr...

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Bibliographic Details
Published inarXiv.org
Main Authors Takagi, S, Subedi, A, Cooper, V R, Singh, D J
Format Paper
LanguageEnglish
Published Ithaca Cornell University Library, arXiv.org 16.08.2010
Subjects
First principles
Mathematical analysis
Niobium oxides
Perovskites
Polarization
Sodium
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Summary:We investigate the effect of \(A\)-site size differences in the double perovskites BiScO\(_3\)-\(M\)NbO\(_3\) ($M$$=\(Na, K and Rb) using first-principles calculations. We find that the polarization of these materials is 70\)\sim\(90 \)\mu\(C/cm\)^2\( along the rhombohedral direction. The main contribution to the high polarization comes from large off-centerings of Bi ions, which are strongly enhanced by the suppression of octahedral tilts as the \)M\( ion size increases. A high Born effective charge of Nb also contributes to the polarization and this contribution is also enhanced by increasing the \)M$ ion size.
ISSN:2331-8422
DOI:10.48550/arxiv.1008.2782