中国物理B ›› 2015, Vol. 24 ›› Issue (9): 97103-097103.doi: 10.1088/1674-1056/24/9/097103

• CONDENSED MATTER: ELECTRONIC STRUCTURE, ELECTRICAL, MAGNETIC, AND OPTICAL PROPERTIES • 上一篇    下一篇

Electronic structures and elastic properties of monolayer and bilayer transition metal dichalcogenides MX2 (M= Mo, W; X= O, S, Se, Te): A comparative first-principles study

曾范a b c, 张卫兵b, 唐壁玉a c   

  1. a Department of Physics, Xiangtan University, Xiangtan 411105, China;
    b School of Physics and Electronic Sciences, Changsha University of Science and Technology, Changsha 410114, China;
    c School of Chemistry and Chemical Engineering, Guangxi University, Nanning 530004, China
  • 收稿日期:2015-03-25 修回日期:2015-04-24 出版日期:2015-09-05 发布日期:2015-09-05
  • 基金资助:
    Project supported by the Construct Program of the Key Discipline in Hunan Province, China and Aid Program for Science and Technology Innovative Research Team in Higher Educational Institutions of Hunan Province, China.

Electronic structures and elastic properties of monolayer and bilayer transition metal dichalcogenides MX2 (M= Mo, W; X= O, S, Se, Te): A comparative first-principles study

Zeng Fan (曾范)a b c, Zhang Wei-Bing (张卫兵)b, Tang Bi-Yu (唐壁玉)a c   

  1. a Department of Physics, Xiangtan University, Xiangtan 411105, China;
    b School of Physics and Electronic Sciences, Changsha University of Science and Technology, Changsha 410114, China;
    c School of Chemistry and Chemical Engineering, Guangxi University, Nanning 530004, China
  • Received:2015-03-25 Revised:2015-04-24 Online:2015-09-05 Published:2015-09-05
  • Contact: Zhang Wei-Bing, Tang Bi-Yu E-mail:zhangwb@csust.edu.cn;tangbiyu@gxu.edu.cn
  • Supported by:
    Project supported by the Construct Program of the Key Discipline in Hunan Province, China and Aid Program for Science and Technology Innovative Research Team in Higher Educational Institutions of Hunan Province, China.

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摘要： First-principle calculations with different exchange-correlation functionals, including LDA, PBE, and vdW-DF functional in the form of optB88-vdW, have been performed to investigate the electronic and elastic properties of two-dimensional transition metal dichalcogenides (TMDCs) with the formula of MX2(M= Mo, W; X = O, S, Se, Te) in both monolayer and bilayer structures. The calculated band structures show a direct band gap for monolayer TMDCs at the K point except for MoO2 and WO2. When the monolayers are stacked into a bilayer, the reduced indirect band gaps are found except for bilayer WTe2, in which the direct gap is still present at the K point. The calculated in-plane Young moduli are comparable to that of graphene, which promises possible application of TMDCs in future flexible and stretchable electronic devices. We also evaluated the performance of different functionals including LDA, PBE, and optB88-vdW in describing elastic moduli of TMDCs and found that LDA seems to be the most qualified method. Moreover, our calculations suggest that the Young moduli for bilayers are insensitive to stacking orders and the mechanical coupling between monolayers seems to be negligible.

关键词: transition metal dichalcogenides, bilayer structures, elastic properties, electronic structure

Abstract: First-principle calculations with different exchange-correlation functionals, including LDA, PBE, and vdW-DF functional in the form of optB88-vdW, have been performed to investigate the electronic and elastic properties of two-dimensional transition metal dichalcogenides (TMDCs) with the formula of MX2(M= Mo, W; X = O, S, Se, Te) in both monolayer and bilayer structures. The calculated band structures show a direct band gap for monolayer TMDCs at the K point except for MoO2 and WO2. When the monolayers are stacked into a bilayer, the reduced indirect band gaps are found except for bilayer WTe2, in which the direct gap is still present at the K point. The calculated in-plane Young moduli are comparable to that of graphene, which promises possible application of TMDCs in future flexible and stretchable electronic devices. We also evaluated the performance of different functionals including LDA, PBE, and optB88-vdW in describing elastic moduli of TMDCs and found that LDA seems to be the most qualified method. Moreover, our calculations suggest that the Young moduli for bilayers are insensitive to stacking orders and the mechanical coupling between monolayers seems to be negligible.

Key words: transition metal dichalcogenides, bilayer structures, elastic properties, electronic structure

中图分类号:  (Total energy and cohesive energy calculations)

  • 71.15.Nc
62.20.de (Elastic moduli) 62.20.dj (Poisson's ratio) 73.22.-f (Electronic structure of nanoscale materials and related systems)