Orbital-Free Density Functional Theory: Linear Scaling Methods for Kinetic Potentials, and Applications to Solid Al and S

TL;DR

This paper explores linear scaling methods for the kinetic potential in orbital-free density functional theory, demonstrating accurate results for aluminum but highlighting challenges with silicon and suggesting new approaches for covalent systems.

Contribution

It introduces and evaluates nonlocal kinetic potentials for solid-state systems, revealing their strengths and limitations in modeling extended covalent materials.

Findings

Accurate results for aluminum using nonlocal kinetic potentials.

Less satisfactory results for silicon highlight the need for improved methods.

A different integration pathway may help address current limitations.

Abstract

In orbital-free density functional theory the kinetic potential (KP), the functional derivative of the kinetic energy density functional, appears in the Euler equation for the electron density and may be more amenable to simple approximations. We study properties of two solid-state systems, Al and Si, using two nonlocal KPs that gave good results for atoms. Very accurate results are found for Al, but results for Si are much less satisfactory, illustrating the general need for a better treatment of extended covalent systems. A different integration pathway in the KP formalism may prove useful in attacking this fundamental problem.