Dependence of Electronic and Optical Properties of MoS2 Multilayers on the Interlayer Coupling and Van Hove Singularity

Nanoscale Research Letters

Zi-Zhong Zhu¹  Jia-Qi Hu¹  Xiao-Hong Shi¹  Shun-Qing Wu¹  Kai-Ming Ho² 

[1] Department of Physics, OSED, Key Laboratory of Low Dimensional Condensed Matter Physics (Department of Education of Fujian Province), Jiujiang Research Institute, Xiamen University;International Center for Quantum Design of Functional Materials (ICQD), University of Science and Technology of China;

关键词: MoS2 multilayers;    Electronic properties;    Optical properties;    Van Hove singularities;   

DOI  :  10.1186/s11671-019-3105-9

来源: DOAJ

【 摘 要 】

Abstract In this paper, the structural, electronic, and optical properties of MoS2 multilayers are investigated by employing the first-principles method. Up to six-layers of MoS2 have been comparatively studied. The covalency and ionicity in the MoS2 monolayer are shown to be stronger than those in the bulk. As the layer number is increased to two or above two, band splitting is significant due to the interlayer coupling. We found that long plateaus emerged in the imaginary parts of the dielectric function ε2xxω $$ {\varepsilon}_2^{xx}\left(\omega \right) $$ and the joint density of states (JDOS) of MoS2 multilayers, due to the Van Hove singularities in a two-dimensional material. One, two and three small steps appear at the thresholds of both the long plateau of ε2xxω $$ {\varepsilon}_2^{xx}\left(\omega \right) $$ and JDOS, for monolayer, bilayer, and trilayer, respectively. As the number of layers further increased, the number of small steps increases and the width of the small steps decreases accordingly. Due to interlayer coupling, the longest plateau and shortest plateau of JDOS are from the monolayer and bulk, respectively.

【 授权许可】

Unknown