Microwave photoresistance in an ultra-high-quality GaAs quantum well

The temperature dependence of microwave-induced resistance oscillations (MIRO), according to the theory, originates from electron-electron scattering. This scattering affects both the quantum lifetime, or the density of states, and the inelastic lifetime, which governs the relaxation of the nonequilibrium distribution function. Here, we report on MIRO in an ultra-high-mobility (μ>3×107cm2/V s) two-dimensional electron gas at T between 0.3 and 1.8 K. In contrast to theoretical predictions, the quantum lifetime is found to be T independent in the whole temperature range studied. At the same time, the T dependence of the inelastic lifetime is much stronger than can be expected from electron-electron interactions.