Abstract
We have studied insulator–quantum Hall–insulator (I-QH-I) transitions in a gated two-dimensional GaAs electron gas containing InAs quantum dots. In this system Shubnikov–de Haas oscillations are observed in both the low-field and high-field insulating regimes, showing that Landau quantization and localization can coexist. A phase diagram is constructed based on our experimental results, and we see that the critical points of the I-QH-I transitions do not correspond to crossover from localization to Landau quantization. Moreover, good scaling behavior is observed on both sides of low- and high-field I-QH transitions.
- Received 20 December 2002
DOI:https://doi.org/10.1103/PhysRevB.69.073311
©2004 American Physical Society