Dynamic Hubbard model for solids with hydrogen-like atoms

TL;DR

This paper introduces a dynamic Hubbard model with an auxiliary spin to better capture electron interactions in solids with hydrogen-like atoms, revealing significant shifts in electronic band structures compared to traditional models.

Contribution

It presents a novel dynamic Hubbard model incorporating an auxiliary spin, improving the description of electron correlations in hydrogen-like atom solids.

Findings

Significant shifts in energy band positions and widths.

Enhanced modeling of electron-electron interactions.

Potential implications for band structure predictions.

Abstract

We discuss how to construct a tight binding model Hamiltonan for the simplest possible solid, composed of hydrogen-like atoms. A single orbital per atom is not sufficient because the on-site electron-electron repulsion mixes in higher energy orbitals. The essential physics is captured by a dynamic Hubbard model with one electronic orbital and an auxiliary spin degree of freedom per site. We point out that this physics can lead to a substantial shift in the position and width of electronic energy bands relative to what is predicted by conventional band structure calculations.