单层VCl3和VBr3中相互作用导致的量子反常霍尔绝缘体到莫特绝缘体相变

Correlation-driven topological phase transition from quantum anomalous Hall insulator to Mott insulator in monolayer VCl3 and VBr3

基于第一性原理计算,发现在不考虑3d电子间关联作用的情况下,二维单层材料VCl3和VBr3是面内铁磁半导体,并且具有量子反常霍尔效应。VCl3能隙约为3.4 meV,VBr3没有全局的能隙。有趣的是,VCl3的陈数为3,有3个手性边缘态;VBr3的陈数为1,对应1个手性边缘态。当考虑关联作用U后,它们会变为Mott绝缘体。对于VCl3,相变点发生在U=0.45 eV;对于VBr3,相变点发生在U=0.35 eV。

Based on the first-principle calculations,we propose that the monolayer VCl3 and VBr3 are quantum anomalous Hall insulators with in-plane magnetization without considering the correlation effect of the 3d electron-electron interaction.The band gap is predicted to be about 3.4 meV for VCl3,but no global gap for VBr3.It is interesting to note that VCl3(VBr3)possesses a Chern number of C=3(C=1)with three(one)chiral edge states.After considering correlation effect,we obtain Mott insulator if U>0.45(U>0.35)eV for VCl3(VBr3).