Dynamical excitonic effects in metals and semiconductors

TL;DR

This paper investigates how dynamical electron-hole interactions influence optical spectra in metals and semiconductors, showing that including these effects improves agreement with experimental data.

Contribution

It demonstrates the significance of dynamical excitonic effects in the Bethe--Salpeter equation, which were previously overlooked, and illustrates their impact on absorption spectra.

Findings

Dynamical effects significantly alter absorption spectra.

Inclusion of dynamical corrections improves agreement with experiments.

Dynamical effects partially cancel self-energy effects.

Abstract

The dynamics of an electron--hole pair induced by the time--dependent screened Coulomb interaction is discussed. In contrast to the case where the static electron--hole interaction is considered we demonstrate the occurrence of important dynamical excitonic effects in the solution of the Bethe--Salpeter equation.This is illustrated in the calculated absorption spectra of noble metals (copper and silver) and silicon. Dynamical corrections strongly affect the spectra, partially canceling dynamical self--energy effects and leading to good agreement with experiment.