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arXiv 1607.01429cond-mat.mtrl-scicond-mat.mes-hallphysics.chem-phphysics.comp-ph
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用修正的k.p方案精确计算电子性质的第一性原理

Enabling accurate first-principle calculations of electronic properties with a corrected k.p scheme

Kristian Berland, Clas Persson

摘要:

提出了一种基于k. p的插值方法,该方法可以将稀疏采样k点网格的特征值和动量矩阵元素扩展到密集采样网格。密集采样,通常需要准确地描述传输和光学性质的散装材料,可以要求计算,例如,在密度泛函理论(DFT)的混合泛函或与微扰扩展超出DFT,如$GW$方法的组合。该方案基于求解k.p方法并从多个参考k点外推。它包括一个校正项,减少了所需的空频带的数量,并改善了频带不连续性。我们展示了如何该计划可以用来产生准确的能带结构,态密度和介电函数。给出了几个例子,使用传统和混合泛函,与Si,TiNiSn,和Cu作为模型材料。我们说明,d-电子和半芯状态,这是特别具有挑战性的k.p方法,可以处理的校正方案,如果稀疏的网格不是太稀疏。

英文摘要:

A computationally inexpensive k.p-based interpolation scheme is developed that can extend the eigenvalues and momentum matrix elements of a sparsely sampled k-point grid into a densely sampled one. Dense sampling, often required to accurately describe transport and optical properties of bulk materials, can be demanding to compute, for instance, in combination with hybrid functionals in density functional theory (DFT) or with perturbative expansions beyond DFT such as the $GW$ method. The scheme is based on solving the k.p method and extrapolating from multiple reference k-points. It includes a correction term that reduces the number of empty bands needed and ameliorates band discontinuities. We show how the scheme can be used to generate accurate band structures, density of states, and dielectric functions. Several examples are given, using traditional and hybrid functionals, with Si, TiNiSn, and Cu as model materials. We illustrate that d-electron and semi-core states, which are particular challenging for the k.p method, can be handled with the correction scheme if the sparse grid is not too sparse.

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