title: Reorientation of anisotropy in a square well quantum hall sample.
abstract: We have measured magnetotransport at half-filled high Landau levels in a quantum well with two occupied electric subbands. We find resistivities that are isotropic in perpendicular magnetic field but become strongly anisotropic at nu = 9/2 and 11/2 on tilting the field. The anisotropy appears at an in-plane field, B(ip) approximately 2.5 T, with the easy-current direction parallel to B(ip) but rotates by 90 degrees at B(ip) approximately 10 T and points now in the same direction as in single-subband samples. This complex behavior is in quantitative agreement with theoretical calculations based on a unidirectional charge density wave state model.
authors.affiliation: Department of Electrical Engineering, Princeton University, Princeton, New Jersey 08544, USA.
authors.forename: W
authors.initials: W
authors.lastname: Pan
authors.forename: T
authors.initials: T
authors.lastname: Jungwirth
authors.forename: H L
authors.initials: HL
authors.lastname: Stormer
authors.forename: D C
authors.initials: DC
authors.lastname: Tsui
authors.forename: A H
authors.initials: AH
authors.lastname: MacDonald
authors.forename: S M
authors.initials: SM
authors.lastname: Girvin
authors.forename: L
authors.initials: L
authors.lastname: Smrcka
authors.forename: L N
authors.initials: LN
authors.lastname: Pfeiffer
authors.forename: K W
authors.initials: KW
authors.lastname: Baldwin
authors.forename: K W
authors.initials: KW
authors.lastname: West