Floating of critical states and the QH to insulator transition

The transition from the quantum Hall state to the insulator is considered for non-interacting electrons in a two-dimensional disordered lattice model with perpendicular magnetic field. Using correlated random disorder potentials the floating up of the critical states can be observed in a similar way as in the continuum model. Thus, the peculiar behaviour of the lattice models reported previously originates in the special choice of uncorrelated random disorder potentials.