Defect-induced overshoot of quantum Hall plateaus

Studies on magnetoresistance in the quantum Hall regime show that defects induced by proton irradiation strongly change the transport properties of an AlGaAs/GaAs two-dimensional electron gas. In particular, it is shown that the overshoot of the quantized value of the Hall resistance at odd filling factors can be introduced by these defects. A model, that explains the observation and assumes that the defects which have spins are essential for mediating the electron scattering in the two-dimensional electron gas, is presented.