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基于密度泛函理论的第一性原理平面波赝势方法,研究了单层二硫化钨(WS2)在掺杂Cr和Mo后能带结构的变化,探索不同原子和掺杂量对能带结构的影响,分析了导致能带结构变化的物理机理。计算结果表明:当掺杂量较高时,Mo对单层WS2的能带结构几乎没有影响,而Cr则影响很大,表现为Cr掺杂时能带结构由直接带隙变为间接带隙,且带隙宽度随着掺杂量的增加而逐渐减小。Cr掺杂后所产生的应力是导致能带结构发生变化的直接原因。通过对态密度和电荷密度的分析,揭示了能带变化的根本原因在于Brillouin区中Γ点和K点的本征能量对掺杂所产生的应力的敏感程度不同。
Based on the first-principle plane-wave pseudopotential method of density functional theory (DFT), the change of the band structure of single-layer tungsten disulfide (WS2) doped with Cr and Mo was studied. The effects of different atoms and dopants on the band structure Influence, analysis of the physical mechanism leading to changes in the band structure. The calculated results show that when the doping amount is high, Mo has almost no effect on the energy band structure of single-layer WS2, while Cr has a great influence on the band structure. The band structure changes from direct band gap to indirect band gap , And the band gap width decreases with the increase of doping amount. The stress caused by Cr doping is the direct reason for the change of the band structure. The analysis of the density of states and the charge density reveals that the fundamental reason for the change of energy band is that the intrinsic energies at Γ and K in the Brillouin region are different from those induced by the doping.