Magneto-optical probing of weak disorder in a two-dimensional hole gas

TL;DR

This paper uses magneto-photoluminescence to investigate a two-dimensional hole gas, revealing the energy spectrum of trions, impurity effects, and providing a sensitive method to detect weak disorder and measure hole cyclotron mass.

Contribution

It introduces a novel magneto-optical technique to probe weak disorder and determine hole cyclotron mass in a two-dimensional hole gas.

Findings

Identification of the three-level energy spectrum of a free positive trion.

Detection of acceptor-bound trions and their cyclotron replica.

Shake-up peaks as sensitive indicators of impurities and hole cyclotron mass.

Abstract

In two-beam magneto-photoluminescence spectra of a two-dimensional valence hole gas we identify the three-level energy spectrum of a free positive trion with a field-induced singlet-triplet transition. The recombination spectrum of acceptor-bound trions is also detected, including a cyclotron replica corresponding to the hole shake-up process. The emergence of a shake-up peak at low temperature is shown to be a sensitive probe of the presence of a small number of impurities inside the high-mobility quantum well, and its relative position is directly related to the hole cyclotron mass.