Exciton fine structure splitting and linearly polarized emission in strained transition-metal dichalcogenide monolayers
Exciton fine structure splitting and linearly polarized emission in strained transition-metal dichalcogenide monolayers
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DOI：
10.1103/physrevb.106.125303
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发表时间：
2022-09-13
影响因子：
3.7
通讯作者：
Chernikov, Alexey
中科院分区：
文献类型：
--
作者：
Glazov, M. M.;Dirnberger, Florian;Chernikov, Alexey
从理论上研究了各向异性弹性应变对过渡金属二硫化物原子薄晶体激子能谱、精细结构和光学选择规律的影响。应变的存在打破了布里渊区K点的手性选择规则，使光学跃迁线极化。诱导线极化的方向与应变张量的主轴有关。弹性应变为激子精细结构的分裂提供了一个附加的贡献，这与从单轴应变的WSe2单层得到的实验证据一致。外加应变还引起动量依赖的塞曼分裂。根据应变的方向和大小，激子能谱中可以形成具有线性色散的狄拉克点。我们提供了应变效应的对称分析，并为激子精细结构哈密顿量的所有相关应变诱导贡献发展了微观理论。
We study theoretically the effects of an anisotropic elastic strain on the exciton energy spectrum fine structure and optical selection rules in atomically thin crystals based on transition-metal dichalcogenides. The presence of strain breaks the chiral selection rules at the K points of the Brillouin zone and makes optical transitions linearly polarized. The orientation of the induced linear polarization is related to the main axes of the strain tensor. Elastic strain provides an additive contribution to the exciton fine structure splitting, in agreement with experimental evidence obtained from the uniaxially strained WSe2 monolayer. The applied strain also induces momentum-dependent Zeeman splitting. Depending on the strain orientation and magnitude, Dirac points with a linear dispersion can be formed in the exciton energy spectrum. We provide a symmetry analysis of the strain effects and develop a microscopic theory for all relevant strain-induced contributions to the exciton fine structure Hamiltonian.