论文标题
通过筛选电势的随机整合在二维材料中有效的GW计算
Efficient GW calculations in two dimensional materials through a stochastic integration of the screened potential
论文作者
论文摘要
多体扰动理论方法（例如$ g_0w_0 $近似）能够准确预测几类材料的Quasiparticle（QP）属性。然而，由于二维（2D）半导体的QP频带结构的计算是已知需要非常致密的BZ采样的，这是由于介电矩阵在长波长限制中的急剧依赖性（$ \ Mathbf {Q}} \ 0 $）。在这项工作中，我们通过将蒙特卡洛集成与插值方案相结合，能够在计算出的网格点之间表示筛选的电位，从而显示如何相对于BZ采样的QP校正相对于BZ采样的收敛性。该方法已通过计算三种不同原型单层材料的带隙：一种过渡金属二色核酸（MOS $ _2 $），宽带隙绝缘子（HBN）和各向异性半导体（磷烯）。拟议的方案表明，这三种材料的间隙通过使用$ \ k $ - 点网格与DFT计算所需的网格相当，同时保持网格统一，从而实现了这三种材料的差异。
Many-body perturbation theory methods, such as the $G_0W_0$ approximation, are able to accurately predict quasiparticle (QP) properties of several classes of materials. However, the calculation of the QP band structure of two-dimensional (2D) semiconductors is known to require a very dense BZ sampling, due to the sharp $q$-dependence of the dielectric matrix in the long-wavelength limit ($\mathbf{q} \to 0$). In this work, we show how the convergence of the QP corrections of 2D semiconductors with respect to the BZ sampling can be drastically improved, by combining a Monte Carlo integration with an interpolation scheme able to represent the screened potential between the calculated grid points. The method has been validated by computing the band gap of three different prototype monolayer materials: a transition metal dichalcogenide (MoS$_2$), a wide band gap insulator (hBN) and an anisotropic semiconductor (phosphorene). The proposed scheme shows that the convergence of the gap for these three materials up to 50meV is achieved by using $\k$-point grids comparable to those needed by DFT calculations, while keeping the grid uniform.
