Phase diagram of the integer quantum Hall effect

The phase diagram of the integer quantum Hall effect is numerically determined in the tight-binding model, which can account for overall features of recently obtained experimental phase diagram with direct transitions from high plateau states to the insulator. In particular, the quantum Hall plateaus are terminated by two distinct insulating regimes, characterized by the Hall resistance with classic and quantized values, respectively, which is also in good agreement with experiments. The physical origin of this peculiar phase diagram is discussed