Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: 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 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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The categories of this paper are: eess
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The categories of this paper are: math-ph
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The categories of this paper are: patt-sol
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The categories of this paper are: math
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The categories of this paper are: stat
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The categories of this paper are: bayes-an
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The categories of this paper are: hep-ex
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The categories of this paper are: atom-ph
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The categories of this paper are: alg-geom
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The categories of this paper are: hep-th
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The categories of this paper are: chem-ph
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The categories of this paper are: q-fin
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The categories of this paper are: cmp-lg
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The categories of this paper are: nucl-ex
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The categories of this paper are: comp-gas
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The categories of this paper are: plasm-ph