Insulator–quantum Hall liquid transitions in a two-dimensional electron gas using self-assembled InAs dots

We investigate the transport properties of two-dimensional electron gases (2DEG) formed in a GaAs/AlGaAs quantum well, where self-assembled InAs quantum dots were grown at the center of the GaAs well. Due to the resulting strain fields repulsive short-range scattering is experienced by the conduction electrons in the 2DEG. In a perpendicular magnetic field, there are transitions between quantum Hall liquids at filling factors ν=1 and 2 and the insulating phase. We show that the boundary of insulator–Quantum Hall transitions can be identified either by analysing the temperature-independent points in ρxx or from the peaks in σxx at low temperatures and both methods give similar results.