论文标题
在半经典模型中，极性和双偏度倾向的二态趋势
Polaron and bipolaron tendencies in a semiclassical model for hole-doped bismuthates
论文作者
论文摘要
Bismuth Perovskites abio $ _3 $（A = SR，BA）容纳各种特殊现象，包括粘结掺杂时的粘结分配绝缘阶段和高温超导性。尽管这些现象的基础机制仍在争论中，但源自轨道重叠的调制的偏外电子phonon（$ e $ -ph）耦合已成为有前途的候选人。在这里，我们采用经典的蒙特卡洛模拟来研究具有非对角线$ e $ ph相互作用的半经典三轨模型。我们证明了（BI）极性相关性的存在，该相关性在高温下持续存在，并且用于脱离粘结分配的绝缘阶段的孔。使用各种局部数量和晶格自由度之间的时空回归分析，我们还确定了在微观水平上键成分的绝缘子的加热和掺杂诱导的融化之间的相似性。我们的结果表明，（BI）Polaron物理可以是一个统一的概念，可以帮助我们理解丰富的二氧化碳相图。
Bismuth perovskites ABiO$_3$ (A = Sr, Ba) host a variety of peculiar phenomena including bond-disproportionated insulating phases and high-temperature superconductivity upon hole doping. While the mechanisms underlying these phenomena are still debated, off-diagonal electron-phonon ($e$-ph) coupling originating from the modulation of the orbital overlaps has emerged as a promising candidate. Here, we employ classical Monte Carlo simulations to study a semiclassical three-orbital model with off-diagonal $e$-ph interactions. We demonstrate the existence of a (bi)polaron correlations that persists in the model at high temperatures and for hole doping away from the bond-disproportionated insulating phase. Using a spatiotemporal regression analysis between various local quantities and the lattice degrees of freedom, we also identify the similarity between heating- and doping-induced melting of a bond-disproportionated insulator at a microscopic level. Our results imply that (bi)polaron physics can be a unifying concept that helps us understand the rich bismuth perovskite phase diagram.
