论文标题
分析对角线G和子空间W近似在完全自洽的GW计算中，用于散装半导体系统
Analysis of diagonal G and subspace W approximations within fully self-consistent GW calculations for bulk semiconducting systems
论文作者
论文摘要
现在可以使用完全自吻合的GW（SC-GW）方法来评估各种分子和散装系统的准粒子和光谱特性。但是，基于G和W的完整矩阵的此类技术在计算上是要求的。常规使用的单发GW-Approximation（G0W0）对选择初始交换相关功能的选择不良。在文献中，许多所谓的自洽的GW方法基于G的对角线近似和W的低级别近似。因此，值得检查与完整矩阵方法相比，此类近似值的良好程度。在这项工作中，我们将Alas，ALP，GAP和ZNS视为原型系统，通过使用平面波基集表达完整的G矩阵来执行SC-GW计算。我们将我们的SC-GW结果与对角线G和子空间W近似SC-GW结果（SC-GW-DIAGG和SC-GW-SUBW方法）进行了比较。在SC-GW-DIAGG方法中，相互作用的G在非相互作用G的特征向量中扩展，因此只保留了对角元素，而在SC-GW-SUBW计算中截断了特征模的数量。提出了对从上述技术获得的结果的系统分析。近似和完整矩阵SC-GW方法之间的准粒子带隙的差异大多小于1.7％，以验证这种广泛采用的近似值，还显示了如何使用这种低级别近似值来包括顶点校正等高阶术语。
Fully self-consistent GW (sc-GW) methods are now available to evaluate quasiparticle and spectral properties of various molecular and bulk systems. However, such techniques based on the full matrix of G and W are computationally demanding. The routinely used single-shot GW-approximation (G0W0) has an undesirable dependency on the choice of initial exchange-correlation functional. In the literature, many so-called self-consistent GW methods are based on diagonal approximation of G and low-ranking approximation of W. It is thus worth to check how good such approximations are in comparison with the full matrix method. In this work, we consider AlAs, AlP, GaP, and ZnS as the prototype systems to perform sc-GW calculations by expressing the full G matrix using a plane-wave basis set. We compared our sc-GW results with the diagonal G and subspace W approximated sc-GW results (sc-GW-diagG and sc-GW-subW methods). In the sc-GW-diagG method, interacting G is expanded in the eigenvectors of non-interacting G such that only diagonal elements are retained, whereas, the number of eigenmodes is truncated in sc-GW-subW calculations. A systematic analysis of the results obtained from the above techniques is presented. The differences in the quasiparticle bandgap between the approximated and the full matrix sc-GW approaches are mostly less than 1.7% that validates such widely adopted approximations, and also shows how such low-ranking approximation can be used to include higher-order terms like the vertex correction.
