Abstract
By adopting the first-principles plane wave pseudopotential method based on density functional theory, the electronic structure properties of single-layer MoS2 (molybdenum disulfide) crystals under biaxial strain are studied. The calculation results in this paper show that when a small strain is applied to a single-layer MoS2, its band structure changes from a direct band gap to an indirect band gap. As the strain increases, the energy band still maintains the characteristics of the indirect band gap, and the band gap shows a linear downward trend. Through further analysis of the density of states, sub-orbital density of states, thermodynamic parameters and Raman spectroscopy, it revealed the variation of single-layer MoS2 with strain. This provides a theoretical basis for realizing the strain regulation of MoS2.
Highlights
2 shows the energy band structure of a single layer of MoS2 under different tensileFigure stresses. It canthe be energy seen from thestructure energy band structure that no stress is ap2 shows band of a single layer of when
AsHumberto shown in Terrones a tensile strain
The interaction between the Mo 3d state electrons and the S 2p state electrons is more enhanced. This means that the conduction band position is offset downwards under compressive strain. This shows that, compared with tensile strain, the band gap of MoS2 becomes narrower under compressive strain
Summary
The experimental results show that the two Raman modes E12g and A1g exhibit a strong thickness dependence Xin He et al studied the energy band changes of WS2 and MoS2 under strain through photoluminescence spectroscopy and first-principles calculations [24]. Through structurethe willphysical be analyzed, and theof changes in its band electronic structure, first-principles band calculations, mechanism the formation of structure, a single-layer thermodynamic parameters will bestructure, studied by applying stress. Mainly uses density functional theory (DFT) to calculate and analyze the related properThe first-principles method in this paper was based on the CASTEP module of Maties of MoS2 [28].
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