Temperature and magnetization-dependent band-gap renormalization and optical many-body effects in diluted magnetic semiconductors

TL;DR

This paper investigates how Coulomb interactions cause band-gap renormalization in GaMnAs, influenced by temperature, magnetization, and carrier density, with implications for understanding ferromagnetism in diluted magnetic semiconductors.

Contribution

It provides a detailed calculation of many-body band-gap renormalization in GaMnAs considering temperature, magnetization, and impurity effects, highlighting its potential as an experimental probe.

Findings

Large band gap renormalization (~0.1 eV) observed.

Ferromagnetic transition enhances band gap renormalization.

Impurity scattering affects the magnitude of gap narrowing.

Abstract

We calculate the Coulomb interaction induced density, temperature and magnetization dependent many-body band-gap renormalization in a typical diluted magnetic semiconductor GaMnAs in the optimally-doped metallic regime as a function of carrier density and temperature. We find a large (about 0.1 eV) band gap renormalization which is enhanced by the ferromagnetic transition. We also calculate the impurity scattering effect on the gap narrowing. We suggest that the temperature, magnetization, and density dependent band gap renormalization could be used as an experimental probe to determine the valence band or the impurity band nature of carrier ferromagnetism.