Transference of Fermi Contour Anisotropy to Composite Fermions

Abstract

There has been a surge of recent interest in the role of anisotropy in interaction-induced phenomena in two-dimensional (2D) charged carrier systems. A fundamental question is how an anisotropy in the energy-band structure of the carriers at zero magnetic field affects the properties of the interacting particles at high fields, in particular of the composite fermions (CFs) and the fractional quantum Hall states (FQHSs). We demonstrate here tunable anisotropy for holes and hole-flux CFs confined to GaAs quantum wells, via applying \textit{in situ} in-plane strain and measuring their Fermi wavevector anisotropy through commensurability oscillations. For strains on the order of $10^{-4}$ we observe significant deformations of the shapes of the Fermi contours for both holes and CFs. The measured Fermi contour anisotropy for CFs at high magnetic field (${\alpha }_{\mathrm{CF}}$) is less than the anisotropy of their low-field hole (fermion) counterparts (${\alpha }_{\mathrm{F}}$), and closely follows the relation: ${\alpha }_{\mathrm{CF}}=\sqrt{{\alpha }_{\mathrm{F}}}$. The energy gap measured for the $\nu =2/3$ FQHS, on the other hand, is nearly unaffected by the Fermi contour anisotropy up to ${\alpha }_{\mathrm{F}}\sim 3.3$, the highest anisotropy achieved in our experiments.

6 pages, 5 figures

References in corpus (11)

• Band mass anisotropy and the intrinsic metric of fractional quantum Hall systems
• Low-temperature, in situ tunable, uniaxial stress measurements in semiconductors using a piezoelectric actuator
• Transference of Transport Anisotropy to Composite Fermions
• Fractional quantum Hall states in two-dimensional electron systems with anisotropic interactions
• Giant low-temperature piezoresistance effect in AlAs two-dimensional electrons
• Numerical study of anisotropy in a composite Fermi liquid
• Composite Fermions with a Warped Fermi Contour
• Ballistic transport of (001) GaAs 2D holes through a strain-induced lateral superlattice
• Strain-induced Fermi contour anisotropy of GaAs 2D holes
• Anisotropic composite fermions and fractional quantum Hall effect
• Tuning of Fermi Contour Anisotropy in GaAs (001) 2D Holes via Strain

Cited by in corpus (24)

• Chiral Gravitons in Fractional Quantum Hall Liquids
• Anisotropic, two-dimensional, disordered Wigner solid
• Anisotropic effects in two-dimensional materials
• Unconventional anisotropic even-denominator fractional quantum Hall state in a system with mass anisotropy
• Record-quality GaAs two-dimensional hole systems
• Surprising robustness of particle-hole symmetry for composite fermion liquids
• Competition between fractional quantum Hall liquid and Wigner solid at small fillings: Role of layer thickness and Landau level mixing
• Quantum Hall Valley Nematics
• Berry phase of the composite-fermion Fermi Sea: Effect of Landau-level mixing
• Composite fermions in bands with N-fold rotational symmetry
• Geometric Resonance of Four-Flux Composite Fermions
• Connection between Fermi contours of zero-field electrons and $\nu =\frac{1}{2}$ composite fermions in two-dimensional systems
• Valley Stoner Instability of the Composite Fermi Sea
• Screening, Friedel oscillations, RKKY interaction, and Drude transport in anisotropic two-dimensional systems
• Geometry of flux attachment in anisotropic fractional quantum Hall states
• Interaction-dependent anisotropy of fractional quantum Hall states
• Universal Fermi-surface anisotropy renormalization for interacting Dirac fermions with long-range interactions
• Tuning of Fermi Contour Anisotropy in GaAs (001) 2D Holes via Strain
• Valley-tunable, even-denominator fractional quantum Hall state in the lowest Landau level of an anisotropic system
• Ultraclean two-dimensional hole systems with mobilities exceeding 10${}^7$ cm${}^2$/Vs
• Fermi surfaces of composite fermions
• $2{\mathbf{k}}_{\mathbf{F}}$ Density Wave Instability of Composite Fermi Liquid
• Anisotropy and quench dynamics of quasiholes in fractional quantum Hall liquids
• Pseudospin Polarization of Composite Fermions under Uniaxial Strain