title: Competition between a fractional quantum hall liquid and bubble and Wigner crystal phases in the third Landau level.
abstract: Magnetotransport measurements were performed in an ultrahigh mobility GaAs/AlGaAs quantum well of density approximately 3.0 x 10(11) cm(-2). The temperature dependence of the magnetoresistance Rxx was studied in detail in the vicinity of nu=9/2. In particular, we discovered new minima in Rxx at a filling factor nu approximately 41/5 and 44/5, but only at intermediate temperatures 80 approximately less than T approximately less than 120 mK. We interpret these as evidence for a fractional quantum Hall liquid forming in the N=2 Landau level and competing with bubble and Wigner crystal phases favored at lower temperatures. Our data suggest that a magnetically driven insulator-insulator quantum phase transition occurs between the bubble and Wigner crystal phases at T=0.
authors.affiliation: Department of Physics and Department of Applied Physics, Columbia University, New York, New York 10027, USA.
authors.forename: G
authors.initials: G
authors.lastname: Gervais
authors.forename: L W
authors.initials: LW
authors.lastname: Engel
authors.forename: H L
authors.initials: HL
authors.lastname: Stormer
authors.forename: D C
authors.initials: DC
authors.lastname: Tsui
authors.forename: K W
authors.initials: KW
authors.lastname: Baldwin
authors.forename: K W
authors.initials: KW
authors.lastname: West
authors.forename: L N
authors.initials: LN
authors.lastname: Pfeiffer