论文标题

单共振拉曼光谱的第一原理计算单层Mote $ _2 $

First-principles calculations of double resonance Raman spectra for monolayer MoTe$_2$

论文作者

Huang, Jianqi, Guo, Huaihong, Zhou, Lin, Zhang, Shishu, Tong, Lianming, Saito, Riichiro, Yang, Teng, Zhang, Zhidong

论文摘要

由于双共振拉曼(DRR)光谱是激光能量依赖性的,因此二维材料的DRR的第一原理计算具有挑战性。在这里,单层MOTE $ _2 $的DRR频谱是由家庭制造程序计算的,其中我们将{\ em abInitio}密度功能性主理学计算与电子 - phonon Wannier(EPW)方法相结合。在四阶扰动理论中,我们不仅能够量化偶极子近似中的电子 - 光子矩阵元素,还可以使用Wannier函数来量化电子 - phonon矩阵元素。实现了计算出的拉曼光谱和实验性拉曼光谱之间的合理一致性,在其中我们从石墨烯中重现了过渡金属二甲构代化(TMDC)的一些独特特征(例如,涉及电子或孔的主要间隔过程)。此外,我们对布里鲁因区域上可能的DRR模式进行分析,突出了低对称点的作用。某些DRR模式的拉曼张量通过第一原理计算给出,从中获得激光极化依赖性。

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.

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