Ab initio study of lattice dynamics of group IV semiconductors using pseudohybrid functionals for extended Hubbard interactions

TL;DR

This paper employs ab-initio extended Hubbard functionals to accurately compute lattice dynamics of group IV semiconductors, improving predictions of phonon properties and thermal conductivities with computational efficiency suitable for high-throughput studies.

Contribution

It introduces a self-consistent approach using pseudohybrid functionals for extended Hubbard interactions in lattice dynamics calculations, enhancing accuracy over traditional functionals.

Findings

Extended Hubbard functional yields higher phonon velocities.

Improved agreement with experimental thermal conductivities.

Computational cost comparable to local functionals.

Abstract

We study the lattice dynamics of group IV semiconductors using fully ab-initio extended Hubbard functional. The onsite and intersite Hubbard interactions are determined self-consistently with recently developed pseudohybrid functionals and included in force calculations. We analyze the Pulay forces by the choice of atomic orbital projectors and the force contribution of the onsite and intersite Hubbard terms. The phonon dispersions, Gruneisen parameters, and lattice thermal conductivities of diamond, silicon, and germanium, which are most-representative covalent-bonding semiconductors, are calculated and compared with the results using local, semilocal, and hybrid functionals. The extended Hubbard functional produces increased phonon velocities and lifetimes, and thus lattice thermal conductivities compared to local and semilocal functionals, agreeing with experiments very well. Considering that our computational demand is comparable to simple local functionals, this work thus suggests a way to perform high-throughput electronic and structural calculations with a higher accuracy.