Yin Zhewen, Panaccione Wyatt, Hu Anjun, Douglas Ossie R T, Tanjil Md Rubayat-E, Jeong Yunjo, Zhao Huijuan, Wang Michael Cai
Department of Mechanical Engineering, University of South Florida, Tampa, Florida 33620, United States.
Department of Medical Engineering, University of South Florida, Tampa, Florida 33620, United States.
Nano Lett. 2023 Dec 27;23(24):11763-11770. doi: 10.1021/acs.nanolett.3c03706. Epub 2023 Dec 15.
Understanding the phonon characteristics of two-dimensional (2D) molybdenum ditelluride (MoTe) under strain is critical to manipulating its multiphysical properties. Although there have been numerous computational efforts to elucidate the strain-coupled phonon properties of monolayer MoTe, empirical validation is still lacking. In this work, monolayer 1H-MoTe under uniaxial strain is studied via micro-Raman spectroscopy. Directionally dependent monotonic softening of the doubly degenerate in-plane E phonon mode is observed with increasing uniaxial strain, where the E peak red-shifts -1.66 ± 0.04 cm/% along the armchair direction and -0.80 ± 0.07 cm/% along the zigzag direction. The corresponding Grüneisen parameters are calculated to be 1.09 and 0.52 along the armchair and zigzag directions, respectively. This work provides the first empirical quantification and validation of the orientation-dependent strain-coupled phonon response in monolayer 1H-MoTe and serves as a benchmark for other prototypical 2D transition-metal tellurides.
了解二维（2D）二碲化钼（MoTe）在应变下的声子特性对于调控其多物理性质至关重要。尽管已经有大量的计算工作来阐明单层MoTe的应变耦合声子性质，但仍缺乏实验验证。在这项工作中，通过显微拉曼光谱研究了单轴应变下的单层1H-MoTe。随着单轴应变的增加，观察到双重简并面内E声子模式的方向依赖性单调软化，其中E峰沿扶手椅方向红移-1.66±0.04 cm/%，沿锯齿方向红移-0.80±0.07 cm/%。沿扶手椅和锯齿方向计算得到的相应格林艾森参数分别为1.09和0.52。这项工作首次对单层1H-MoTe中取向依赖的应变耦合声子响应进行了实验量化和验证，并为其他典型的二维过渡金属碲化物提供了一个基准。
