Anomalous Robustness of theν=5/2Fractional Quantum Hall State near a Sharp Phase Boundary

Yang Liu, D. Kamburov, M. Shayegan, L. N. Pfeiffer, K. W. West, K. W. Baldwin
2011 Physical Review Letters  
We report magneto-transport measurements in wide GaAs quantum wells with tunable density to probe the stability of the fractional quantum Hall effect at filling factor $\nu = $ 5/2 in the vicinity of the crossing between Landau levels (LLs) belonging to the different (symmetric and antisymmetric) electric subbands. When the Fermi energy ($E_F$) lies in the excited-state LL of the symmetric subband, the 5/2 quantum Hall state is surprisingly stable and gets even stronger near this crossing, and
more » ... this crossing, and then suddenly disappears and turns into a metallic state once $E_F$ moves to the ground-state LL of the antisymmetric subband. The sharpness of this disappearance suggests a first-order transition.
doi:10.1103/physrevlett.107.176805 pmid:22107557 fatcat:3hmm6hldnrbzrffgubp2vukbca