title: Density-induced interchange of anisotropy axes at half-filled high Landau levels.
abstract: We observe density-induced 90 degrees rotations of the anisotropy axes in transport measurements at half-filled high Landau levels in the two dimensional electron system, where stripe states are proposed ( nu = 9/2, 11/2, etc.). Using a field effect transistor, we find the transition density to be 2.9x10(11) cm(-2) at nu = 9/2. Hysteresis is observed in the vicinity of the transition. We construct a phase boundary in the filling factor magnetic field plane in the regime 4.4<nu<4.6. An in-plane magnetic field applied along either anisotropy axis always stabilizes the low density orientation of the stripes.
authors.affiliation: Department of Physics, Columbia University, New York, New York 10027, USA.
authors.forename: J
authors.initials: J
authors.lastname: Zhu
authors.forename: W
authors.initials: W
authors.lastname: Pan
authors.forename: H L
authors.initials: HL
authors.lastname: Stormer
authors.forename: L N
authors.initials: LN
authors.lastname: Pfeiffer
authors.forename: K W
authors.initials: KW
authors.lastname: West