Imaging of low compressibility strips in the quantum Hall liquid
Abstract
Many physicists surmise that incompressible strips formed near the edges of quantum Hall devices govern the physics of this effect. Using scanning capacitive microscopy we image in detail strips corresponding to several integer quantum Hall filling factors. <A HREF=http://xxx.lanl.gov/abs/cond-mat/9910061>[cond- mat/9910061]</A> By passing a tunneling current between the scanning tip and the 2DEG for short periods of time we create a persistent dome-shape enhancement of local density by ~ 20%, several microns in diameter. At high magnetic field the strips of low compressibility are formed in the perturbed area. Contrary to the term "incompressible", we find that in moderate mobility samples the 2DEG inside the strips has a low but nonzero compressibility. The observed strips aslo appear significantly wider than predicted by theory. We presented a qualitative explanation, which accounts for the discrepancy in the strip width by considering a disorder-induced nonzero density of states in the cyclotron gap.
- Publication:
-
APS March Meeting Abstracts
- Pub Date:
- March 2000
- Bibcode:
- 2000APS..MARI17012F