Hybrid atomic orbital basis from first principles: Bottom-up mapping of self-energy correction to large covalent systems

TL;DR

This paper introduces a first-principles method to construct hybrid atomic orbitals that enable efficient transfer of self-energy corrected tight-binding parameters across large covalent systems, improving computational efficiency.

Contribution

It proposes a novel hybrid atomic orbital basis derived from first principles that simplifies and accelerates the transfer of self-energy corrections in large covalent systems.

Findings

Self-energy corrections are localized within the third nearest neighbor.

The basis allows transfer of parameters with minimal additional cost.

The approach enables inexpensive estimation of quasi-particle structures.

Abstract

Construction of hybrid atomic orbitals is proposed as the approximate common eigen states of finite first moment matrices. Their hybridization and orientation can be a-priori tunned as per their anticipated neighbourhood. Their Wannier function counterparts constructed from the Kohn-Sham(KS) single particle states constitute an orthonormal multi-orbital tight-binding(TB) basis resembling hybrid atomic-orbitals locked to their immediate atomic neighborhood, while spanning the subs-space of KS states. The proposed basis thus not only renders predominantly single TB parameters from first-principles for each nearest neighbour bonds involving no more than two orbitals irrespective of their orientation, but also facilitate an easy route for transfer of such TB parameters across isostructural systems exclusively through mapping of neighbourhoods and projection of orbital charge centres. With hybridized 2s,2p and 3s,3p valence electrons, the spatial extent of self-energy correction(SEC) to TB parameters in the proposed basis are found to be localized mostly within the third nearest neighbourhood, thus allowing effective transfer of self-energy corrected TB parameters from smaller reference systems to much larger target systems, with nominal additional computational cost beyond that required for explicit computation of SEC in the reference systems. The proposed approach promises inexpensive estimation of quasi-particle structure of large covalent systems with workable accuracy.