Twisted MX2/MoS2 heterobilayers: effect of van der Waals interaction on the electronic structure
Twisted MX2/MoS2 heterobilayers: effect of van der Waals interaction on the electronic structure
复制标题
扭曲的 MX2/MoS2 异质双层：范德华相互作用对电子结构的影响
DOI：
10.1039/c7nr07746g
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发表时间：
2017-12-28
期刊：
影响因子：
6.7
通讯作者：
Zeng, Xiao Cheng
中科院分区：
文献类型：
--
作者：
Lu, Ning;Guo, Hongyan;Zeng, Xiao Cheng
采用第一性原理方法研究了二维扭曲过渡金属硫属化物（TMDC）异质双层膜MX 2/MoS 2（M = Mo，Cr，W; X = S，Se）在不同旋转角度下的电子性质.货车德瓦耳斯（vdW）相互作用被发现对二维（2D）TMDC异质双分子层的电子结构有重要影响。与非扭曲的异质双分子层相比，扭曲的异质双分子层的层间距离明显增加，从而改变了异质双分子层的vdW相互作用以及MX 2/MoS 2系统的电子结构。结果表明，对于CrSe 2/MoS 2和MoSe 2/MoS 2系统，间接带隙（G-K）显著增大（约0.1eV），导致间接-直接带隙转变。在13.2度和46.8度之间的扭转角下，对于整个样品上的失配晶格，层间距离几乎是恒定的，导致几乎相同的电子结构。即使考虑了自旋-轨道耦合（SOC）效应，由于大的自旋-轨道分裂，WS 2/MoS 2异质双分子层仍将发生间接-直接跃迁.
A comprehensive first-principles study of the electronic properties of twisted 2D transition metal dichalcogenide (TMDC) heterobilayers MX2/MoS2 (M = Mo, Cr, W; X = S, Se) with different rotation angles has been performed. The van der Waals (vdW) interaction is found to have an important effect on the electronic structure of two-dimensional (2D) TMDC heterobilayers. Compared to non-twisted heterobilayers, the interlayer distance of twisted heterobilayers increases appreciably, thereby changing the vdW interaction of the heterobilayers as well as the electronic structure of the MX2/MoS2 systems. As a result, for CrSe2/MoS2 and MoSe2/MoS2 systems, the indirect bandgap (G-K) exhibits a notable enlargement (about 0.1 eV), leading to the indirect-to-direct gap transition. At twisting angles between 13.2 degrees and 46.8 degrees, the interlayer distance is nearly constant for the mismatched lattices over the entire sample, resulting in nearly the same electronic structure. Even after considering the spin-orbit coupling (SOC) effect, the indirect-to-direct transition is still predicted to occur in the WS2/MoS2 heterobilayer due to the large spin-orbit splitting.