TDDFT calculations for excitation spectra of III-V ternary alloys

TL;DR

This paper employs TDDFT with LASTO basis and cluster averaging to accurately compute excitation spectra of III-V ternary alloys, integrating mGGA for self-energy corrections to match experimental data.

Contribution

It introduces a combined TDDFT and cluster averaging approach using mGGA for accurate optical spectra of semiconductor alloys.

Findings

Good agreement with experimental excitation spectra

Wave functions from LDA suffice with mGGA corrections

Method applicable to arbitrary alloy concentrations

Abstract

We adopted the time-dependent density functional theory (TDDFT) within the linear augmented Slater-type orbitals (LASTO) basis and the cluster averaging method to compute the {\color{red}excitation} spectra of III-V ternary alloys with arbitrary concentration $x$. The TDDFT was carried out with the use of adiabatic meta-generalized gradient approximation (mGGA), which contains the $1/q^2$ singularity in the dynamical exchange-correlation kernel ($f_{XC,00}(\mathbf{q})$) as $q\rightarrow 0$. We found that by using wave functions obtained in local density approximation (LDA) while using mGGA to compute self-energy correction to the band structures, we can get {\color{red} good overall} agreement between theoretical results and experimental data for the excitation spectra. Thus, our studies provide some insight into the theoretical calculation of optical spectra of semiconductor alloys.