Avoided Band Crossings: Tuning Metal-Insulator Transitions in Chaotic Systems

Abstract

We show that avoided crossings of energy bands may give rise to a variety of phenomena such as transitions from metal to insulator and vice versa, changes in localization lengths, and changes in the fractal dimension of energy spectra. We explain the occurrence of these phenomena in the kicked Harper model under classically chaotic conditions and predict them to occur in other systems.

4 pages, 5 figures, minor changes (figure completed, typo corrected), to appear in Phys. Rev. Lett