Ab initio calculation of excitonic effects in the optical spectra of semiconductors

TL;DR

This paper presents an ab initio method for calculating excitonic effects in the optical spectra of semiconductors, improving agreement with experimental data by solving the Bethe--Salpeter equation based on quasiparticle bandstructure.

Contribution

It introduces a novel ab initio approach that accurately models excitonic effects in optical spectra using the Bethe--Salpeter equation starting from quasiparticle calculations.

Findings

Enhanced accuracy in peak positions and lineshape of silicon's optical spectrum

Significant improvement over previous theoretical calculations

Method applicable to other semiconductors and insulators

Abstract

An ab initio approach to the calculation of excitonic effects in the optical absorption spectra of semiconductors and insulators is formulated. It starts from a quasiparticle bandstructure calculation and is based on the relevant Bethe--Salpeter equation. An application to bulk silicon shows a substantial improvement with respect to previous calculations in the description of the experimental spectrum, for both peak positions and lineshape.