Cr和W掺杂的单层MoS2电子结构的第一性原理研究

摘要

采用密度泛函理论框架下的第一性原理平面波赝势方法，研究了Cr和W掺杂对单层二硫化钼(MoS2)晶体的电子结构性质的影响。计算结果表明：当掺杂浓度较高时， W对MoS2的能带结构几乎没有影响，而Cr的掺杂则影响很大，表现为能带由直接带隙变为间接带隙，且禁带宽度减小。通过进一步分析，得出应力的产生是导致Cr掺杂的MoS2电子结构变化的最直接的原因。%We study the electronic properties of Cr- and W-doped single-layer MoS2 using an abinitio method according to the density functional theory. Our calculated results show the energy band structures of MoS2 are significantly affected by Cr doping, but not by W doping at a high doping concentration. The effects of Cr doping manifest as the transition of energy band structure from direct to indirect, and the decrease of band gap. Our further analysis reveals that strain is the direct reason for the change of electronic structure in the Cr-doped MoS2.