Transport and quantum lifetime dependence on electron density in gated GaAs/AlGaAs heterostructures

We present a study of the transport and quantum lifetime dependence on electron density in two completely different kinds of two-dimensional electron gas systems. We observed that both the two scattering time increase with increasing the electron density. But the ratios of the transport to the quantum lifetime have different tendency with the electron density, which do not conform to the conventional theory. We speculate that the screening effects need to be considered in order to explain our experimental results.