Probing Landau quantisation with the presence of insulator-quantum Hall   transition in a GaAs two-dimensional electron system
  Magneto-transport measurements are performed on the two-dimensional electron system (2DES) in an AlGaAs/GaAs heterostructure. By increasing the magnetic field perpendicular to the 2DES, magnetoresistivity oscillations due to Landau quantisation can be identified just near the direct insulator-quantum Hall (I-QH) transition. However, different mobilities are obtained from the oscillations and transition point. Our study shows that the direct I-QH transition does not always correspond to the onset of strong localisation. 
Kuang Yao Chen, Y. H. Chang, C.-T. Liang, N. Aoki, Y. Ochiai, C. F.   Huang, Li-Hung Lin, K. A. Cheng, H. H. Cheng, H. H. Li...