论文标题
在超级自电性背后的微观机制上
On the microscopic mechanisms behind hyperferroelectricity
论文作者
论文摘要
高空电电的兴趣越来越大，由于其独特的特性，即使在存在去极化场的情况下，也可以保持自发极化。尽管如此，仍然缺少归因于极性$ lo $模式的一般微观机制。 Here, by means of phonons calculations and force constants analysis in two class of hyperferroelectrics, the ABO$_3$-LiNbO3-type systems and the prototypical hexagonal-ABC systems, we unveiled common features in the dynamical properties of a hyperferroelectric behind such $LO$ instability: negative or vanishing on-site force constant associated to the cation driving the $LO$ polar distortion, and destabilizing阳离子 - 氨基酸相互作用，都是由短距离力诱导的。我们还通过施加外部正压来预测超级自利特特性的可能增强。压力加强了不稳定的短距离相互作用。特别是，在压力下，与不稳定的$ lo $模式相关的模式有效费用的增加表明，在压缩应变下，$ d $ = 0极化的最终增强。
Hyperferroelectrics are receiving a growing interest thanks to their unique property to retain a spontaneous polarization even in presence of a depolarizing field. Nevertheless, general microscopic mechanisms driving hyperferroelectricity, which is ascribed to the softening of a polar $LO$ mode, are still missing. Here, by means of phonons calculations and force constants analysis in two class of hyperferroelectrics, the ABO$_3$-LiNbO3-type systems and the prototypical hexagonal-ABC systems, we unveiled common features in the dynamical properties of a hyperferroelectric behind such $LO$ instability: negative or vanishing on-site force constant associated to the cation driving the $LO$ polar distortion, and destabilizing cation-anion interactions, both induced by short-range forces. We also predict possible enhancement of the hyperferroelectric properties by applying an external positive pressure; pressure strengthens the destabilizing short-range interactions. Particularly, the increase in the mode effective charges associated to the unstable $LO$ mode under pressure suggests an eventual enhancement of the $D$=0 polarization under compressive strain.
