标题： 二维TMDs中导带电子导致带隙减小的理论：虚频形式主义 显示英文标题

标题： Theory of Band Gap Reduction Due to Conduction Electrons in 2D TMDs: Imaginary Frequency Formalism

摘要： 二维（2D）过渡金属二硫属化物（TMDs）具有较大的直接带隙，该带隙已被实验观察到随着电荷载流子密度（掺杂）的增加而减小。 这一效应近年来已通过各种方法和近似进行了理论研究。 在本工作中，我们基于虚频形式的费曼图技术发展了带隙重整化的理论。 我们考虑了导带电子的动态屏蔽，使用随机相位近似（RPA），以及来自金属栅极的屏蔽。 虽然我们的理论适用于任何二维半导体，但为了具体起见，我们考虑了MoS$_2$和 WSe$_2$并与现有的实验数据进行比较。 在这两种情况下，我们在相对较低的载流子密度下计算出了很大的带隙重整化，达到几百meV。 这与实验数据有很好的一致性。 显示英文摘要

摘要： Two Dimensional (2D) Transition Metal Dichalcogenides (TMDs) possess a large direct band gap which has been experimentally observed to shrink with increasing charge carrier density (doping). The effect has been the subject of theoretical study in recent years using various approaches and approximations. In this work we develop the theory of bandgap renormalization based on Feynman diagrammatic technique in the imaginary frequency formalism. We consider dynamical screening from conduction band electrons using the random phase approximation (RPA), as well as screening from a metallic gate. While our theory is general for any 2D semiconductor, to be specific we consider MoS$_2$ and WSe$_2$ and compare with available experimental data. In both cases we calculate large band gap renormalization that reaches several hundred meV at relatively low carrier density. This is in good agreement with experimental data.