The Fermi edge singularity of spin polarized electrons

TL;DR

This paper investigates how spin polarization in a 2D electron gas affects its absorption spectrum, revealing differences explained by Mahan excitons and Fermi edge singularities.

Contribution

It demonstrates the impact of spin polarization on absorption spectra and distinguishes the mechanisms of Mahan excitons versus Fermi edge singularities.

Findings

Absorption spectra differ in magnitude, linewidth, and filling factor dependence with spin polarization.

Creation of Mahan excitons versus Fermi edge singularities explains spectral differences.

Spin polarization influences the dominant many-body effects in 2DEG absorption.

Abstract

We study the absorption spectrum of a two-dimensional electron gas (2DEG) in a magnetic field. We find that that at low temperatures, when the 2DEG is spin polarized, the absorption spectra, which correspond to the creation of spin up or spin down electron, differ in magnitude, linewidth and filling factor dependence. We show that these differences can be explained as resulting from creation of a Mahan exciton in one case, and of a power law Fermi edge singularity in the other.