单层金属卤化物CoX_2(X=Cl、Br、I)可调能隙和磁性研究

本文采用密度泛函理论系统的研究了二维单层金属卤化物CoX_2(X=Cl,Br,I)的结构稳定性、电子性质和磁性质.三种卤化物的束缚能分别是9.01、8.04和6.95 eV,表明Co原子和卤素原子间存在强相互作用.三种材料的能带结构都显示了间接带隙半导体特性.三种材料的总磁矩都是3 μ_B,主要来源于Co原子的磁矩.为了实现对材料物性的调控,我们考虑了双轴应变.发现压缩应变不仅可以显著增强铁磁态的稳定性,还可以实现体系从间接带隙半导体向直接带隙半导体的转变.

Research on tunable band gap and magnetism of monolayer metal halides CoX2 (X=Cl, Br, I)

The structural stability, electronic and magnetic properties of monolayer mental halides CoX2 (X= Cl, Br, I) are studied by using density functional theory. The binding energies of the three halides are 9.01, 8.04 and 6.95eV respectively, indicating a strong interaction between Co atom and halide atoms. All of them show indirect band gap semiconductor characteristics. The total magnetic moments of the three materials are 3 B, mainly from the magnetic moment of Co atom. In order to adjust the physical properties of these systems, we have considered the biaxial strain. Most importantly, we find that the compression strain can not only significantly enhance the stability of ferromagnetic states, but also realize the transition from indirect band gap semiconductors to direct band gap semiconductors.