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arXiv · 1008.2782

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

S. Takagi·A. Subedi·V. R. Cooper·D. J. Singh
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Abstract

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 $μ$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.

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S. Takagi, A. Subedi, V. R. Cooper, D. J. Singh. 2010-08-16. Effect of $A$-site size difference on polar behavior in $M$BiScNbO$_6$,($M$$=$Na, K and Rb): Density functional calculations. https://doi.org/10.1103/physrevb.82.134108

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