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Vibration response of monolayer1H−MoTe2to equibiaxial strain
Physical Review B ( IF 3.7 ) Pub Date : 2020-11-25 , DOI: 10.1103/physrevb.102.195431
Wei Yang , Ling-Yu Zhu , Tian Zhou , Tao-Jun Yang , Yi-Bo Yan , Jia-Jun Li , Fa-Wei Zheng , Yu Yang , Xiao-Hui Wang , Wen-Bo Xu , Ping Zhang

Based on density functional theory and density functional perturbation theory calculations, we systematically investigate the vibration responses of monolayer 1HMoTe2 to equibiaxial strains. It is found that, at the Γ point, the frequency shift of Raman-active modes (E, A1, and E) and infrared-active modes (A2 and E) show domelike shapes; that is, their frequencies decrease monotonically under tensile strains but first increase and then decrease rapidly under compressive strains. The frequency-shift behaviors are revealed to come from vibration responses to both bond stretching and bond-angle bending in strained 1HMoTe2. At the K point, a special acoustic mode becomes soft because its frequency drops to zero at a compressive strain of 11.27%. We find that electron occupancies in Mo dz2, Te px, and Te py orbitals weaken the vibration mode at K, which exhibits the in-plane vibration of Mo atoms and out-of-plane vibration of Te atoms. On the other hand, compressive strains enhance the Fermi surface nesting and abruptly soften the vibration frequency for one acoustic mode at K. Our results point out a way to detect the strain status of monolayer 1HMoTe2 by measuring the vibration frequencies.

中文翻译:

单层1H-MoTe2对等双轴应变的振动响应

基于密度泛函理论和密度泛函摄动理论计算,我们系统地研究了单层的振动响应 1个H-Te2等轴应变。发现,在Γ 点,拉曼激活模式的频移 Ë 一种1个Ë'' 和红外激活模式 一种2''Ë呈圆顶状;也就是说,它们的频率在拉伸应变下单调降低,但在压缩应变下先升高然后迅速降低。揭示了频移行为来自对应变中键拉伸和键角弯曲的振动响应1个H-Te2。在ķ 特殊的声学模式变得柔和,因为在压缩应变为 -11.27。我们发现Mo中的电子占有率dž2,Te pXpÿ 轨道削弱了振动模式 ķ表现出Mo原子的面内振动和Te原子的面外振动。另一方面,压缩应变增强了费米表面的嵌套,并突然软化了一个声学模式下的振动频率。ķ。我们的结果指出了一种检测单层应变状态的方法1个H-Te2 通过测量振动频率。
更新日期:2020-11-25
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