Transferability of self-energy correction in tight-binding basis constructed from first principles

TL;DR

This paper presents a transferable, computationally efficient method to estimate self-energy corrections in large systems using localized orbitals derived from smaller systems, applicable to various nanoribbons.

Contribution

The authors introduce a scheme to transfer self-energy corrections from small to large systems via localized orbitals, reducing computational cost for large-scale calculations.

Findings

SEC strengthens pi bonds and transfers charge from edge to bulk in nanoribbons.

SEC enhances inter-sublattice spin separation in magnetic bipartite systems.

The method accurately estimates band-gap corrections without explicit SEC calculations.

Abstract

We demonstrate in this work the transferability of self-energy(SE) correction(SEC) of Kohn-Sham(KS) single particle states from smaller to larger systems, when mapped through localized orbitals constructed from the KS states. The approach results in a SE corrected TB framework, within which, the mapping of SEC of TB parameters is found to be transferable from smaller to larger systems of similar morphology, leading to a computationally inexpensive approach for estimation of SEC in large systems with reasonably high accuracy. The scheme has been demonstrated in insulating, semiconducting and magnetic nanoribbons of graphene and hexagonal boron nitride, where SEC tends to strengthen the individual pi bonds, leading to transfer of charge from edge to bulk. Additionally in magnetic bipartite systems SEC tends to enhance inter-sublattice spin separation. The proposed scheme thus promises to enable estimation of SEC of band-gaps of large systems without needing to explicitly calculate SEC of KS single particle levels which can be computationally prohibitively expensive.