Abstract
We present activation gap measurements of the fractional quantum Hall effect (FQHE) in the second Landau level. Signatures for 14 (5) distinct incompressible FQHE states are seen in a high- (low-) mobility sample with the enigmatic 5 2 even-denominator FQHE having a large activation gap of ∼500 (∼250) mK in the high- (low-) mobility sample. This is the largest gap ever reported for the 5 2 FQHE state. Our measured large relative gaps for 5 2, 7 3, and 8 3 FQHEs indicate the emergence of exotic FQHE correlations in the second Landau level, possibly different from the well-known lowest-Landau-level Laughlin correlations. Our measured 5 2 gap is found to be in reasonable agreement with the theoretical gap once finite-width and disorder-broadening corrections are taken into account.
Original language | English (US) |
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Article number | 081301 |
Journal | Physical Review B - Condensed Matter and Materials Physics |
Volume | 77 |
Issue number | 8 |
DOIs | |
State | Published - Feb 1 2008 |
Externally published | Yes |
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics