Thickness and strain effects on electronic structures of transition metal dichalcogenides: 2H-M X2 semiconductors (M = Mo, W; X = S, Se, Te)
Thickness and strain effects on electronic structures of transition metal dichalcogenides: 2H-M X2 semiconductors (M = Mo, W; X = S, Se, Te)
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DOI：
10.1103/physrevb.85.033305
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发表时间：
2012-01-17
影响因子：
3.7
通讯作者：
Lee, J. D.
中科院分区：
文献类型：
--
作者：
Yun, Won Seok;Han, S. W.;Lee, J. D.
用第一性原理计算方法研究了2H-MX-2(M=Mo，W；X=S，Se，Te)的电子结构。当层数减少到单层时，块体的间接带隙变为具有较大带隙的直接带隙，带曲率导致有效质量的剧烈变化。另一方面，当应变作用于单层时，直接缝隙变为间接缝隙，有效质量发生变化。特别是，拉应变降低了能隙和有效质量，而压应变则使能隙和有效质量增大。此外，更大的拉应力会导致
Using the first-principles calculations, we explore the electronic structures of 2H-M X-2 (M = Mo, W; X = S, Se, Te). When the number of layers reduces to a single layer, the indirect gap of bulk becomes a direct gap with larger gap and the band curvatures are found to lead to the drastic changes of effective masses. On the other hand, when the strain is applied on the single layer, the direct gap becomes an indirect gap and the effective masses vary. Especially, the tensile strain reduces the gap energy and effective masses while the compressive strain enhances them. Furthermore, the much larger tensile stress leads to become