We have investigated the small-signal frequency response of the GaAs/AlGaAs two-dimensional electron system in the reentrant insulating phase around the ν = 1/5 fractional quantum Hall liquid from 0.2 to 2 MHz in the presence of a DC bias. When the sample is DC biased above the nonlinear conduction threshold, the insulating state exhibits an inductive AC response as the imaginary component of the conductivity (Im δxx) becomes negative. Moreover, Im δxx shows a broad minimum near a frequency which increases with increasing DC bias, in a manner consistent with the washboard oscillations of a magnetic-field-induced Wigner crystal.
All Science Journal Classification (ASJC) codes
- Condensed Matter Physics
- Materials Chemistry
- A. heterojunctions
- D. fractional quantum Hall effect
- D. quantum localization