Time-resolved photoluminescence of a two-dimensional hole system in the extreme quantum limit.

Abstract

We report time-resolved and continuous-wave magnetoluminescence measurements on a two-dimensional hole system in a GaAs/${\mathrm{Al}}_{\mathit{x}}$${\mathrm{Ga}}_{1\mathrm{\ensuremath{-}}\mathit{x}}$As quantum well. The dominant spectral emission line in the absence of magnetic field and at high Landau-level filling factor \ensuremath{\nu} has a short recombination lifetime, characteristic of extended hole states. Two additional lines appearing at \ensuremath{\nu}\ensuremath{\lesssim}1/3 have long lifetimes, signaling the recombination of localized holes. The fraction of localized holes abruptly increases below \ensuremath{\nu}=1/3.