Magnetic field induced Mott transition of a one-component electron plasma in GaAs quantum wells

We have measured the time-resolved magneto-photoluminescence of mixed type GaAsAlAs quantum wells, in which the electron density can be varied from ∼109 to ∼1011 cm−2. We confirm that as the electron density is increased the precursor of the Mott transition is the trion (negatively charged exciton) and that the transition occurs when the Landau level filling factor v = 2. In zero field the transition is broad and ill-defined, but in a field it is sharp and is accompanied by an abrupt change in linewidth and radiative lifetime.