Block-Diagonalization and f-electron Effects in Tight-Binding Theory

TL;DR

This paper extends tight-binding total energy methods to include f-electrons, demonstrating accurate and transferable parameters for a range of elements, with a focus on block-diagonalization for improved fitting.

Contribution

It introduces a block-diagonalization approach in tight-binding models to accurately incorporate f-electron effects across multiple elements.

Findings

F-electron tight-binding parameters are as accurate as d-electron ones.

Block-diagonalization is essential for reliable parameter fitting.

The method applies successfully from Be to U.

Abstract

We extend a tight-binding total energy method to include f-electrons, and apply it to the study of the structural and elastic properties of a range of elements from Be to U. We find that the tight-binding parameters are as accurate and transferable for f-electron systems as they are for d-electron systems. In both cases we have found it essential to take great care in constraining the fitting procedure by using a block-diagonalization procedure, which we describe in detail.