多铁性材料的第一性原理模型哈密顿量研究

First-principles effective Hamiltonian modeling of multiferroic materials

由于在某些多铁性材料中存在着自旋、轨道和晶格等多种自由度的强耦合,它们会表现出丰富而有趣的相图与物理性质。但目前第一性原理方法还不能直接用来研究这些材料在有限温度下的物理性质。而基于第一性原理的有效哈密顿量方法却可突破这一限制。文章通过介绍几项研究工作,包括磁致铁电体RMn2O5和CuO的相图,以及RMn2O5中的电磁子,来说明这个方法在多铁性材料研究中的应用。

Because of the strong coupling between the spin, orbital, and lattice degrees of freedom, multiferroic materials display very rich and novel physics. However, first-principles meth-ods so far still cannot be applied directly to study the finite temperature properties of multiferroic materials. The first-principles effective Hamiltonian methods, on the contrary, can be used. In this review we introduce these methods and their applications in studying the phase diagrams of magne-to-ferroelectrics RMn2O5 and CuO, and the electromagnon in RMn2O5.