Shake-up Processes in a Low-Density Two-Dimensional Electron Gas: Spin-Dependent Transitions to Higher Hole Landau Levels

TL;DR

This paper presents a theoretical study of shake-up processes in a low-density two-dimensional electron gas under strong magnetic fields, revealing sharp Fano resonances and the role of Coulomb interactions in optical transitions.

Contribution

It introduces a detailed theory of spin-dependent shake-up processes and correlated states in a 2DEG, highlighting optically-active three-particle states and their spectral features.

Findings

Presence of sharp Fano resonances in spectra

Identification of optically-active three-particle states

Relation between shake-ups in 2DEG and 2DHG

Abstract

A theory of shake-up processes in photoabsorption of an interacting low-density two-dimensional electron gas (2DEG) in strong magnetic fields is presented. In these processes, an incident photon creates an electron-hole pair and, because of Coulomb interactions, simultaneously excites one particle to higher Landau levels (LL's). In this work, the spectra of correlated charged spin-singlet and spin-triplet electron-hole states in the first hole LL and optical transitions to these states (i.e., shake-ups to the first hole LL) are studied. Our results indicate, in particular, the presence of optically-active three-particle quasi-discrete states in the exciton continuum that may give rise to surprisingly sharp Fano resonances in strong magnetic fields. The relation between shake-ups in photoabsorption of the 2DEG and in the 2D hole gas (2DHG), and shake-ups of isolated negative X^- and positive X^+ trions are discussed.