Figure 3: FQH Effect in the first LL.
(a) ρxx(n, B) from v=2 to v=5, measured at B=14 T, T=30 mK (Device B). FQH states follow the CF sequence p/(2p±1) between each integer up to v=5. 7/3 is poorly resolved in this device, but this is not a generic feature. No FQH states are seen beyond v=5. (b–d) Temperature dependence of the FQH states in the v=2 to 3, v=3 to 4 and v=4 to 5 sequences (Device A). Temperatures range from 500 mK to 4 K. ρxx exponentially vanishes as T is lowered. Contrary to Device B, the 7/3 state is visible in this device. (e) ρxx and σxy in the v=2 to 3 sequence, measured at B=14 T and T=30 mK (Device A). Plateaus of σxy are seen at filling factors 7/3, 12/5, 13/5, 8/3. FQH states are observed in ρxx at v=17/7 and 18/7 but are not resolved in σxy. (f) ρxx observed in the v=2 to v=3 sequence (45 T, T=400 mK, Device A). FQH states are observed at denominators up to 11. (g) Field dependence of the activation gaps for Device B at v=8/3 (red), 11/3 (black) and 13/3 (yellow). Error bars correspond to 1-σ confidence interval.
