Density-based mixing parameter for hybrid functionals

TL;DR

This paper introduces a density-based method to determine the mixing parameter in hybrid functionals for DFT, improving accuracy across different materials while maintaining computational efficiency.

Contribution

It proposes a novel approach to calculate the hybrid functional mixing parameter directly from electronic density, reducing errors for various band gap materials.

Findings

Significantly reduces errors in hybrid functional calculations.

Maintains good structural property descriptions.

Implementation adds negligible computational cost.

Abstract

A very popular ab-initio scheme to calculate electronic properties in solids is the use of hybrid functionals in density functional theory (DFT) that mixes a portion of Fock exchange with DFT functionals. In spite of their success, a major problem still remains, related to the use of one single mixing parameter for all materials. Guided by physical arguments that connect the mixing parameter to the dielectric properties of the solid, and ultimately to its band gap, we propose a method to calculate this parameter from the electronic density alone. This method is able to cut significantly the error of traditional hybrid functionals for large and small gap materials, while retaining a good description of structural properties. Moreover, its implementation is simple and leads to a negligible increase of the computational time.