title: Enhancement of the ν = 5/2 fractional quantum Hall state in a small in-plane magnetic field.
abstract: Using a 50-nm-width ultraclean GaAs/AlGaAs quantum well, we have studied the Landau level filling factor ν=5/2 fractional quantum Hall effect in a perpendicular magnetic field B∼1.7  T and determined its dependence on tilted magnetic fields. Contrary to all previous results, the 5/2 resistance minimum and the Hall plateau are found to strengthen continuously under an increasing tilt angle 0<θ<25° (corresponding to an in-plane magnetic field 0<B(∥)<0.8  T). In the same range of θ, the activation gaps of both the 7/3 and the 8/3 states are found to increase with tilt. The 5/2 state transforms into a compressible Fermi liquid upon tilt angle θ>60°, and the composite fermion series [2+p/(2p±1), p=1,2] can be identified. Based on our results, we discuss the relevance of a Skyrmion spin texture at ν=5/2 associated with small Zeeman energy in wide quantum wells, as proposed by Wójs et al. [Phys. Rev. Lett. 104, 086801 (2010)].
authors.affiliation: Department of Electrical Engineering, Princeton University, Princeton, New Jersey 08544, USA.
authors.forename: Guangtong
authors.initials: G
authors.lastname: Liu
authors.forename: Chi
authors.initials: C
authors.lastname: Zhang
authors.forename: D C
authors.initials: DC
authors.lastname: Tsui
authors.forename: Ivan
authors.initials: I
authors.lastname: Knez
authors.forename: Aaron
authors.initials: A
authors.lastname: Levine
authors.forename: R R
authors.initials: RR
authors.lastname: Du
authors.forename: L N
authors.initials: LN
authors.lastname: Pfeiffer
authors.forename: K W
authors.initials: KW
authors.lastname: West