First-principles calculations of double resonance Raman spectra for monolayer MoTe2
First-principles calculations of double resonance Raman spectra for monolayer MoTe2
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DOI：
10.1103/physrevb.105.235401
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发表时间：
2022-02
影响因子：
3.7
通讯作者：
Jianqi Huang;Huaihong Guo;Lin Zhou;Shishu Zhang;L. Tong;R. Saito;Teng Yang;Zhidong Zhang
中科院分区：
文献类型：
--
作者：
Jianqi Huang;Huaihong Guo;Lin Zhou;Shishu Zhang;L. Tong;R. Saito;Teng Yang;Zhidong Zhang
由于双共振拉曼(DRR)光谱与激光能量有关，二维材料双共振拉曼光谱的第一性原理计算具有挑战性。本文采用电子-声子Wannier(EPW)方法和密度泛函理论相结合的方法，用自制的程序计算了单层Mote$2的DRR谱。在四阶微扰理论中，我们不仅可以量子化偶极近似下的电子-光子矩阵元，而且可以利用Wannier函数来量子化电子-声子矩阵元。计算的拉曼光谱与实验的拉曼光谱符合得很好，其中我们再现了石墨烯中过渡金属二卤化物(TMDCs)的一些独特特征(例如，主要的谷间过程涉及一个电子或一个空穴)。此外，我们对布里渊区可能存在的DRR模进行了分析，突出了低对称点的作用。通过第一性原理计算给出了某些DRR模的拉曼张量，并由此得到了激光偏振特性。
Since double resonance Raman (DRR) spectra are laser-energy dependent, the first-principles calculations of DRR for two-dimensional materials are challenging. Here, the DRR spectrum of monolayer MoTe$_2$ is calculated by home-made program, in which we combine {\em ab-initio} density-functional-theory calculations with the electron-phonon Wannier (EPW) method. Within the fourth-order perturbation theory, we are able to quantify not only the electron-photon matrix elements within the dipole approximation, but also the electron-phonon matrix elements using the Wannier functions. The reasonable agreement between the calculated and experimental Raman spectra is achieved, in which we reproduce some distinctive features of transition metal dichalcogenides (TMDCs) from graphene (for example, the dominant intervalley process involving an electron or a hole). Furthermore, we perform an analysis of the possible DRR modes over the Brillouin zone, highlighting the role of low-symmetry points. Raman tensors for some DRR modes are given by first principles calculations from which laser polarization dependence is obtained.