论文标题
激子精细结构分裂和线性两极化的二分法单层元素中的线性极化
Exciton fine structure splitting and linearly polarized emission in strained transition-metal dichalcogenide monolayers
论文作者
论文摘要
我们研究了基于过渡金属二核苷的原子 - 薄晶体中对激子的精细结构和光学选择规则的理论上对激子能谱和光学选择规则的影响。应变的存在使手性选择规则在布里渊区的$ \ bm k $点处打破，并使光学转换线性极化。诱导线性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分裂提供了添加贡献，该结构与从单轴紧张的WSE $ _2 $单层获得的实验证据一致。应用应变还诱导动量依赖性的zeeman分裂。根据应变方向和大小，可以在激子能量谱中形成带有线性分散体的狄拉克点。我们提供了对应变效应的对称分析，并为所有相关应变诱导的对激子精细结构Hamiltonian的贡献提供了微观理论。
We study theoretically effects of an anisotropic elastic strain on the exciton energy spectrum fine structure and optical selection rules in atom-thin crystals based on transition-metal dichalcogenides. The presence of strain breaks the chiral selection rules at the $\bm K$-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 uniaxially strained WSe$_2$ 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.
