Weak levitation of 2D delocalized states in a magnetic field.

TL;DR

This paper investigates how weak Landau level mixing causes a slight upward energy shift of delocalized states in a magnetic field, revealing a levitation mechanism independent of Landau level number.

Contribution

It demonstrates that weak Landau level mixing induces a levitation of delocalized states via resonant tunneling, a novel insight into quantum Hall systems.

Findings

Weak Landau level mixing causes energy shift of delocalized states.

Levitation mechanism is independent of Landau level number.

Resonant tunneling 'shunts' saddle points, causing levitation.

Abstract

The deviation of the energy position of a delocalized state from the center of Landau level is studied in the framework of the Chalker-Coddington model. It is demonstrated that introducing a weak Landau level mixing results in a shift of the delocalized state up in energy. The mechanism of a levitation is a neighboring - Landau level - assisted resonant tunneling which ``shunts'' the saddle-points. The magnitude of levitation is shown to be independent of the Landau level number.