Anisotropic transport in unidirectional lateral superlattice around half-filling of the second Landau level

Abstract

We have observed marked transport anisotropy in short period (a=92 nm) unidirectional lateral superlattices around filling factors nu=5/2 and 7/2: magnetoresistance shows a sharp peak for current along the modulation grating while a dip appears for current across the grating. By altering the ratio a/l (with l=sqrt{hbar/eB_perp} the magnetic length) via changing the electron density n_e, it is shown that the nu=5/2 anisotropic features appear in the range 6.6 alt a/l alt 7.2 varying their intensities, becoming most conspicuous at a/l simeq 6.7. The peak/dip broadens with temperature roughly preserving its height/depth up to 250 mK. Tilt experiments reveal that the structures are slightly enhanced by an in-plane magnetic field B_| perpendicular to the grating but are almost completely destroyed by B_| parallel to the grating. The observations suggest the stabilization of a unidirectional charge-density-wave or stripe phase by weak external periodic modulation at the second Landau level.

REVTeX, 5 pages, 3 figures, Some minor revisions, Added notes and references

References in corpus (6)

• Ground state phase diagram of 2D electrons in a high Landau level: - DMRG study
• Experimental Evidence for a Spin-Polarized Ground State in the ν=5/2 Fractional Quantum Hall Effect
• An Investigation of Orientational Symmetry-Breaking Mechanisms in High Landau Levels
• Density Induced Interchange of Anisotropy Axes at Half-Filled High Landau Levels
• Orientation of the Stripe Formed by the Two-Dimensional Electrons in Higher Landau Levels
• Optimal orientation of striped states in the quantum Hall system against external modulations

Cited by in corpus (9)

• Origin of positive magnetoresistance in small-amplitude unidirectional lateral superlattices
• Reorientation of the stripe Phase of 2D Electrons by a Minute Density Modulation
• Impact of the modulation doping layer on the ν=5/2 anisotropy
• Fourier analyses of commensurability oscillations in Fibonacci lateral superlattices
• Geometric resonances in the magnetoresistance of hexagonal lateral superlattices
• Quantum Depinning Transition of Quantum Hall Stripes
• Dynamical Conductivity of Disordered Quantum Hall Stripes
• Collapse of the fractional quantum Hall state by a unidirectional periodic potential modulation
• Modulation Induced Phase Transition from Fractional Quantum Hall to Stripe State at nu=5/3