arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2011.08677cond-mat.mtrl-sci
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在密度泛函理论和其他理论中用于有效计算的智能局域轨道

Smart local orbitals for efficient calculations within density functional theory and beyond

G. Gandus, A. Valli, D. Passerone, R. Stadler

摘要:

局部基组的投影增强波形式主义允许在密度泛函理论(DFT)的计算效率的计算。然而,实现高的数值精度需要一个广泛的基组,这也提出了一个基本的问题,解释的结果。我们提出了一种方法来获得一个约化的原子轨道的基组通过亚对角化的每个原子块的哈密顿量。由此产生的局部轨道(LO)继承了局部晶场的信息。在LO的基础上,很明显,哈密顿量是近块对角,我们证明,它是可能的,以保持只有一个子集的相关LO提供了一个准确的描述周围的费米能级的物理。这在一定程度上减少了原始基组的冗余,同时它允许人们进行DFT计算的后处理,从解释电子输运到提取有效的紧束缚哈密顿量,非常有效,而不会牺牲结果的准确性。

英文摘要:

Localized basis sets in the projector augmented wave formalism allow for computationally efficient calculations within density functional theory (DFT). However, achieving high numerical accuracy requires an extensive basis set, which also poses a fundamental problem for the interpretation of the results. We present a way to obtain a reduced basis set of atomic orbitals through the subdiagonalization of each atomic block of the Hamiltonian. The resulting local orbitals (LOs) inherit the information of the local crystal field. In the LO basis, it becomes apparent that the Hamiltonian is nearly block-diagonal, and we demonstrate that it is possible to keep only a subset of relevant LOs which provide an accurate description of the physics around the Fermi level. This reduces to some extent the redundancy of the original basis set, and at the same time it allows one to perform post-processing of DFT calculations, ranging from the interpretation of electron transport to extracting effective tight-binding Hamiltonians, very efficiently and without sacrificing the accuracy of the results.

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