Effect of Small-Angle Scattering on the Integer Quantum Hall Plateau

A GaAs/AlGaAs two-dimensional electron gas (2DEG) structure with the high mobility of mu_2K=1.78×10⁶cm¹/Vs has been studied by low-temperature Hall and Shubnikov de Hass (SdH) measurements. Quantum lifetimes related to all-angle scattering events reduced from 0.64ps to 0.52ps after illuminating by Dingle plots, and transport lifetimes related to large-angle scattering events increasing from 42.3ps to 67.8ps. These results show that small-angle scattering events become stronger. It is clear that small-angle scattering events can cause the variation of the widths of the quantum Hall plateaus.