Levitation of current carrying states in the lattice model for the integerquantum mall effect

The disorder driven quantum Hall to insulator transition is investigated fo r a two-dimensional lattice model. The Hail conductivity and the localizati on length are calculated numerically near the transition. For uncorrelated and weakly correlated disorder potentials the current carrying states are a nnihilated by the negative Chern states originating from the band center. I n the presence of correlated disorder potentials with correlation length la rger than approximately half the lattice constant the floating up of the cr itical states in energy without merging is observed. This behavior is simil ar to the levitation scenario proposed for the continuum model.