Universal behavior in the floating up of quantum Hall extended states as B arrow 0 and the apparent metal-insulator transition at B = 0
Abstract
We investigate the relationship between the extended states in the quantum Hall regime and the apparent ‘metal’-insulator transition at B = 0 in 2D systems. Using extremely low density, high quality 2D n-GaAs systems (μ_peak = 24 million cm^2V-1s-1) that show an apparent 2D MIT we show that even for magnetic fields as low as 0.025 T the extended states continue to float up in energy. Although there has been numerous studies in different material systems on the relation between the B = 0 MIT and the quantum Hall effect, different conclusions on the fate of the extended states as B arrow 0 have been reached. In this work we provide an explanation as to why these studies have arrived at different conclusions and present a universal quantum Hall-insulator phase diagram that unifies the conflicting results.
- Publication:
-
APS March Meeting Abstracts
- Pub Date:
- March 2002
- Bibcode:
- 2002APS..MARA21011Y