Anisotropic composite fermions and fractional quantum Hall effect

Abstract

We study the role of anisotropy on the transport properties of composite fermions near Landau level filling factor $\nu =1/2$ in two-dimensional holes confined to a GaAs quantum well. By applying a parallel magnetic field, we tune the composite fermion Fermi sea anisotropy and monitor the relative change of the transport scattering time at $\nu =1/2$ along the principal directions. Interpreted in a simple Drude model, our results suggest that the scattering time is longer along the longitudinal direction of the composite fermion Fermi sea. Furthermore, the measured energy gap for the fractional quantum Hall state at $\nu =2/3$ decreases when anisotropy becomes significant. The decrease, however, might partly stem from the charge distribution becoming bilayer-like at very large parallel magnetic fields.

References in corpus (6)

• Band mass anisotropy and the intrinsic metric of fractional quantum Hall systems
• Transference of Transport Anisotropy to Composite Fermions
• Fractional quantum Hall states in two-dimensional electron systems with anisotropic interactions
• Spin-Polarization of Composite Fermions and Particle-Hole Symmetry Breaking
• Composite Fermions with a Warped Fermi Contour
• $\nu =1/2$ Fractional Quantum Hall Effect in Tilted Magnetic Fields

Cited by in corpus (2)

• Tuning of Fermi Contour Anisotropy in GaAs (001) 2D Holes via Strain
• Exchange effect and magneto-plasmon mode dispersion in an anisotropic two-dimensional electronic system