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arXiv 1610.06641cond-mat.mtrl-sci
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用于降维多电子微扰理论计算的布里渊区非均匀采样方案

Non-uniform sampling schemes of the Brillouin zone for many-electron perturbation-theory calculations in reduced dimensionality

Felipe H. da Jornada, Diana Y. Qiu, Steven G. Louie

摘要:

基于多电子微扰理论方法的第一性原理计算,如\textit{ab initio} GW和GW加Bethe-Salpeter方程(GW-BSE)方法,分别是预测材料准粒子和光学性质的可靠方法。然而,这些方法在处理电子-电子相互作用时涉及更多的注意,并且当应用于具有降低的维度的系统时在计算上要求更高,因为电子限制导致布里渊区上的总和收敛较慢,这是由于在介电矩阵的“头”和“颈”元件中表现出的复杂得多的屏蔽环境。在这里,我们提出了两个新的方案来采样的布里渊区GW和GW-BSE计算:非均匀颈部子采样方法和集群采样插值方法,这可以分别用于一个家庭的单粒子问题,如GW计算,并为涉及两个粒子状态的散射的问题,如当解决BSE。我们在几个少层半导体和石墨烯上测试了这些方法,并表明它们对布里渊区进行了更有效的采样,并在计算机时间上减少了两到三个数量级。这两种方法可以很容易地纳入几个\textit{ab initio}包,计算电子和光学性能,通过GW和GW-BSE的方法。

英文摘要:

First principles calculations based on many-electron perturbation theory methods, such as the \textit{ab initio} GW and GW plus Bethe-Salpeter equation (GW-BSE) approach, are reliable ways to predict quasiparticle and optical properties of materials, respectively. However, these methods involve more care in treating the electron-electron interaction and are considerably more computationally demanding when applied to systems with reduced dimensionality, since the electronic confinement leads a slower convergence of sums over the Brillouin zone due to a much more complicated screening environment that manifests in the "head" and "neck" elements of the dielectric matrix. Here, we present two new schemes to sample the Brillouin zone for GW and GW-BSE calculations: the non-uniform neck subsampling method and the clustered sampling interpolation method, which can respectively be used for a family of single-particle problems, such as GW calculations, and for problems involving the scattering of two-particle states, such as when solving the BSE. We tested these methods on several few-layer semiconductors and graphene and show that they perform a much more efficient sampling of the Brillouin zone and yield two to three orders of magnitude reduction in the computer time. These two methods can be readily incorporated into several \textit{ab initio} packages that compute electronic and optical properties through the GW and GW-BSE approaches.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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