拉曼光谱
材料科学
单层
凝聚态物理
带隙
拉伤
极限抗拉强度
密度泛函理论
声子
分子物理学
纳米技术
光学
计算化学
复合材料
物理
光电子学
化学
医学
内科学
作者
Shan Huang,Yanping Wang,Yawen Fan,Jinjiao Feng,Hui Zhao,Yang Zhang
标识
DOI:10.1142/s0217984921501359
摘要
The two-dimensional transition-metal dichalcogenides (2D TMDs) WX 2 (S, Se, Te) have received extensive attention and research since they have excellent physical properties and have been widely used in the fields of photoelectronics. Monolayer (ML) WX 2 has excellent physical properties and can be modified by simple strain. Using the first principles based on density functional theory (DFT), this paper mainly studies the electronic properties of ML WS 2 , WSe 2 and Wte 2 . We also study the stabilities of three ML structures, the changes of Raman spectra and the movement of Raman peaks under biaxial tensile and compressive strains. Under the control of strain not only does the bandgap changes, but also the band properties shift between the direct bandgap and the indirect bandgap. With the increase of strain, bond length and bond angle change in the opposite trend. At the same time, we also studied the phonon dispersion relations of WX 2 under different strains. We found that three structures showed good thermodynamic stabilities under the tensile strain (1–10%). When the compressive strain is 2%, one of the acoustic modes of WS 2 or Wse 2 becomes imaginary at [Formula: see text] point, which indicates the structural instability. When tensile strain Raman summit blueshifts and when compressive strains, the redshift occurs.
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