Coulomb Perturbation by Photoholes of Two-Dimensional Electron Gas Ingaas-Heterojunctions: the Case of Fermi-Edge Singularities

Abstract

Several reports in the past two years have focused on the use of photoluminescence spectroscopy to identify optically details of behaviour of a two-dimensional (2D) electron gas in quantizing magnetic fields in the integer and fractional quantum Hall regimes, and beyond [1-4]. A critical question, of course, is the nature of the connection between such optical information and that derived from transport experiments, specifically in terms of the perturbation which the optically injected holes generate within the 2D electron system. Yet there appears to be little quantitative experimental information about the strength of this interaction to date. A second, and related question concerning the optical spectroscopy of such many electron systems is the issue of the spatial overlap between the photohole and the 2D or a lower dimensional electron gas. In the work so far, single quantum wells and heterojunctions as well as acceptor δ-doping have been employed, so that in terms of controlling the holes’ spatial location considerable variable may occur. In case of the single heterojunction or a very wide quantum well, for example, this raises the question whether the exciton-like luminescence response actually originates from the heterointerface directly or indirectly.