Polaron and bipolaron tendencies in a semiclassical model for hole-doped bismuthates
Abstract
Bismuth perovskites ABiO (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 (-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 -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.
Keywords
Cite
@article{arxiv.2012.01857,
title = {Polaron and bipolaron tendencies in a semiclassical model for hole-doped bismuthates},
author = {Mi Jiang and George A. Sawatzky and Mona Berciu and Steven Johnston},
journal= {arXiv preprint arXiv:2012.01857},
year = {2021}
}