单层Janus MoSSe双共振拉曼散射的理论研究

Theoretical Study on Double Resonant Raman Scattering in Janus MoSSe Monolayer

孙鸿智 孙薇 赵波 郭怀红

Hongzhi Sun Wei Sun Bo Zhao Huaihong Guo

辽宁石油化工大学 理学院，辽宁 抚顺 113001

College of Sciences，Liaoning Petrochemical University，Fushun Liaoning 113001，China

单层Janus MoSSe拉曼光谱中出现的双共振峰，是材料特征的重要指纹。但是，这些双共振峰尚存在起源理解不清、机制亟需澄清的问题。基于密度泛函理论、量子高阶微扰理论和群论分析，系统研究了单层Janus MoSSe的双共振拉曼光谱。研究发现，单层Janus MoSSe的电?光共振耦合过程的倒格子波矢依赖于激光能量，在第一布里渊区中任意波矢 qvec都可能出现。基于群论分析，推导出产生双共振拉曼活性的对称性条件，并阐明了在Janus结构体系中出现大量双共振拉曼峰的根本原因。研究结果可为理解二维Janus结构体系中发生的双共振拉曼过程提供理论指导，并为澄清双共振拉曼峰的起源提供合理的理论手段。

The double resonance Raman (DRR) peaks of Janus MoSSe monolayer are important fingerprints of material characteristics. However, the origin of DRR peaks is still poorly understood and needs urgent clarification. Based on density functional theory, high?order quantum perturbation theory and group theory analysis, the DRR spectra of Janus MoSSe monolayer were studied theoretically and systematically. It is found that the inverse lattice wave vector of the electro?optical resonance coupling process of Janus MoSSe monolayer depends on the laser energy, and any wave vector may appear in the first Brillouin zone. Based on group theory analysis, the symmetry conditions for the generation of DRR activity were deduced, and the fundamental reason for the occurrence of a large number of DRR peaks in the Janus structural system was elucidated. This study provides theoretical guidance for understanding the DRR processes occurring in two?dimensional Janus structural system, and provides a rational theoretical means for clarifying the origin of the DRR peaks.

辽宁省教育厅面上项目(LJKZ0391)

10.3969/j.issn.1672-6952.2022.03.006