Non-linear transport and noise measurements in reentrant integer quantum Hall states*

Two-dimensional electron gas (2DEG) system in strong magnetic field is an ideal platform to explore interesting physics such as reentrant integer quantum Hall (RIQH) effect in second and higher Landau levels. We have carried out non-linear transport and noise measurements in ultra-high mobility GaAs/AlGaAs 2DEG to study RIQH states in Corbino-geometry samples. By increasing the DC bias gradually, we found the insulating phase of RIQH states disappeared, and the depinning trace can be divided into three regions according to different DC bias values. The narrow-band noise only appears in the middle region.