标题： 磁性绝缘体中相分离的蒙特卡罗研究 显示英文标题

标题： Monte Carlo study of phase separation in magnetic insulators

摘要： 在本工作中，我们专注于研究零带宽扩展哈伯德模型中最近邻反铁磁相互作用$J$和局域库仑相互作用$U$的相分离问题。该系统通过蒙特卡洛模拟（在巨正则系综中）在二维正方晶格（具有$N=L\times L =400$个格点）上进行了分析，获得了$U/(4J)=2$随化学势和电子浓度变化的结果。根据相互作用参数的值，系统表现出均匀的（反）铁磁（AF）相或无序（NO）相，以及相分离 PS:AF/NO 状态。均匀相之间的转变（即 AF-NO 转变）可以是一阶或二阶的，并且相图中也存在三临界点。电子压缩性$K$是相分离的指标，该量是本文特别关注的内容。 显示英文摘要

摘要： In this work we focus on the study of phase separation in the zero-bandwidth extended Hubbard with nearest-neighbors intersite Ising-like magnetic interactions $J$ and on-site Coulomb interactions $U$. The system has been analyzed by means of Monte Carlo simulations (in the grand canonical ensemble) on two dimensional square lattice (with $N=L\times L =400$ sites) and the results for $U/(4J)=2$ as a function of chemical potential and electron concentration have been obtained. Depending on the values of interaction parameters the system exhibits homogeneous (anti-)ferromagnetic (AF) or non-ordered (NO) phase as well as phase separation PS:AF/NO state. Transitions between homogeneous phases (i.e. AF-NO transitions) can be of first or second order and the tricritical point is also present on the phase diagrams. The electron compressibility $K$ is an indicator of the phase separation and that quantity is of particular interest of this paper.