On the low-field insulator-quantum Hall conductor transitions
  We studied the insulator-quantum Hall conductor transition which separates the low-field insulator from the quantum Hall state of the filling factor $\nu=4$ on a gated two-dimensional GaAs electron system containing self-assembled InAs quantum dots. To enter the $\nu=4$ quantum Hall state directly from the low-field insulator, the two-dimensional system undergoes a crossover from the low-field localization to Landau quantization. The crossover, in fact, covers a wide range with respect to the magnetic field rather than only a small region near the critical point of the insulator-quantum Hall conductor transition. 
Tsai-Yu Huang, J. R. Juang, C. F. Huang, Gil-Ho Kim, Chao-Ping Huang,   C.-T. Liang, Y. H. Chang, Y. F. Chen, Y. Lee, and D....