Influence of Correlated Disorder Potentials on the Levitation of Current Carrying States in.pdf

Influence of Correlated Disorder Potentials on the Levitation of Current Carrying States in the Quantum Hall Effect 1 0 Th. Koschny and L. Schweitzer∗ 0 2 Physikalisch-Technische Bundesanstalt, Bundesallee 100, 38116 Braunschweig, Germany g u A Abstract 7 The disorder driven quantum Hall to insulator transition is investigated for a two-dimensional lattice system. ] We consider a Gaussian correlated random potential, study the behaviour of the current carrying states and l l trace their energetical position when the disorder strength is increased. Our results qualitatively resemble a those obtained previously for exponentially correlated disorder potentials. We find both the downward h - movement of the anti-Chern states as well as the floating up of the Chern states across the Landau gap s which is sometimes masked by the global broadening of the tight binding band. e m Keywords: Quantum Hall to insulator transition, correlated random potentials, current carrying states . t a m - 1. Introduction In a recent paper we have shown [20] that d n the lattice model can exhibit similar proper- o The disorder driven quantum Hall to insu- ties as the continuum model if long range cor- c lator transition once again became a topic of related random disorder potentials are consid- [ 1 active research recently. The theoretical activ- ered. Using exponentially correlated random v ities undertaken over the past years resulted in potentials to model the intrinsic scattering po- 8 a controversial debate concerning the fate of tentials and other imperfe