Tight-binding model: correction of the d-band approximation

TL;DR

This paper improves the tight-binding model for transition metals by introducing corrections to the d-band approximation, enhancing accuracy in surface energies, binding energies, and magnetic properties.

Contribution

It proposes a simple, more accurate interatomic potential based on distance-dependent hopping parameters and analyzes charge distribution and the Stoner model for ferromagnetic metals.

Findings

Corrected surface and binding energies in transition metals.

Enhanced description of ferromagnetic properties.

More accurate modeling of transition metal alloys.

Abstract

The electronic structure, when restricted to the d-band approximation, is a computational model that is both efficient and useful for describing transition metals. In the absence of considering delocalized sp-states, this approximation gives rise to incorrect surface energies, binding energies, and an inaccurate description of ferromagnetic transition metals. The present work compares the complexity of implementing corrections with the possibility of using an accurate sp-d approach. Basic force fields based on the second moment approximation continue to be utilized for the description of interactions in transition metals. In contrast, the present study proposes an elementary and more accurate interatomic potential based on hopping parameters depending on distances. The charge distribution and the Stoner model are also analyzed to provide appropriate corrections to the tight-binding picture used to describe ferromagnetic metals and alloys.