Enhanced Thermal Hall Effect in Nearly Ferroelectric Insulators
Enhanced Thermal Hall Effect in Nearly Ferroelectric Insulators
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DOI：
10.1103/physrevlett.124.167601
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发表时间：
2020-04-21
影响因子：
8.6
通讯作者：
Sun, Xiao-Qi
中科院分区：
文献类型：
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作者：
Chen, Jing-Yuan;Kivelson, Steven A.;Sun, Xiao-Qi
在最近的实验观察的背景下，一个意想不到的大的霍尔热导率，κ（H），在绝缘的La2CuO4（LCO）和SrTiO3（STO），我们理论上探索的条件下，声学声子可以引起这样一个大的κ（H）。本征和非本征对kappa（H）的贡献都与介电常数ε和“挠曲电”耦合F成比例。虽然内在的贡献仍然是数量级小于所观察到的效果，一个外在的贡献成比例的声子平均自由程似乎可能占的意见，至少在STO。我们预测在某些绝缘钙钛矿中有更大的固有kappa（H）。
In the context of recent experimental observations of an unexpectedly large thermal Hall conductivity, kappa(H), in insulating La2CuO4 (LCO) and SrTiO3 (STO), we theoretically explore conditions under which acoustic phonons can give rise to such a large kappa(H). Both the intrinsic and extrinsic contributions to kappa(H) are large in proportion to the dielectric constant, epsilon, and the "flexoelectric" coupling, F. While the intrinsic contribution is still orders of magnitude smaller than the observed effect, an extrinsic contribution proportional to the phonon mean-free path appears likely to account for the observations, at least in STO. We predict a larger intrinsic kappa(H) in certain insulating perovskites.