A new hybrid LDA and Generalized Tight-Binding method for the electronic structure calculations of strongly correlated electron systems

TL;DR

This paper introduces a hybrid computational approach combining LDA and a generalized tight-binding method to accurately calculate the electronic structure of strongly correlated materials, validated on cuprates.

Contribution

It develops a new hybrid scheme integrating ab initio LDA with a generalized tight-binding method for better electronic structure calculations of strongly correlated systems.

Findings

Accurately reproduces band gaps and dispersions of charge transfer insulators.

Agrees with ARPES experimental data for cuprates.

Provides a reliable framework for strongly correlated electron systems.

Abstract

A novel hybrid scheme is proposed. The {\it ab initio} LDA calculation is used to construct the Wannier functions and obtain single electron and Coulomb parameters of the multiband Hubbard-type model. In strong correlation regime the electronic structure within multiband Hubbard model is calculated by the Generalized Tight-Binding (GTB) method, that combines the exact diagonalization of the model Hamiltonian for a small cluster (unit cell) with perturbation treatment of the intercluster hopping and interactions. For undoped La$_2$CuO$_4$ and Nd$_2$CuO$_4$ this scheme results in charge transfer insulators with correct values of gaps and dispersions of bands in agreement to the ARPES data.