Competition between fractional quantum Hall liquid and Wigner solid at small fillings: Role of layer thickness and Landau level mixing

Abstract

What is the fate of the ground state of a two-dimensional electron system (2DES) at very low Landau level filling factors ($\nu$) where interaction reigns supreme? An ordered array of electrons, the so-called Wigner crystal, has long been believed to be the answer. It was in fact the search for the elusive Wigner crystal that led to the discovery of an unexpected, incompressible liquid state, namely the fractional quantum Hall state at $\nu =1/3$. Understanding the competition between the liquid and solid ground states has since remained an active field of fundamental research. Here we report experimental data for a new two-dimensional system where the electrons are confined to an AlAs quantum well. The exceptionally high quality of the samples and the large electron effective mass allow us to determine the liquid-solid phase diagram for the two-dimensional electrons in a large range of filling factors near $\simeq 1/3$ and $\simeq 1/5$. The data and their comparison with an available theoretical phase diagram reveal the crucial role of Landau level mixing and finite electron layer thickness in determining the prevailing ground states.

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• Two-dimensional electrons occupying multiple valleys in AlAs
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• Model anisotropic quantum Hall states
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• Fractional quantum Hall states in two-dimensional electron systems with anisotropic interactions
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• Probing the geometry of the Laughlin state
• Exact results for model wave functions of anisotropic composite fermions in the fractional quantum Hall effect
• Interplay between fractional quantum Hall liquid and crystal phases at low filling
• Transference of Fermi Contour Anisotropy to Composite Fermions
• Probing the Melting of a Two-dimensional Quantum Wigner Crystal via its Screening Efficiency
• Magnetic Field Induced Insulating Phases at Large $r_s$
• Transition from a fractional quantum Hall liquid to an electron solid at Landau level filling nu = 1/3 in tilted magnetic fields
• Possible observation of phase coexistence of the $\nu =1/3$ fractional quantum Hall liquid and a solid
• Pinning modes of high magnetic field Wigner solids with controlled alloy disorder

Cited by in corpus (13)

• Anisotropic, two-dimensional, disordered Wigner solid
• Chiral Pseudo Spin Liquids in Moire Heterostructures
• Composite fermion pairing induced by Landau level mixing
• Quantum Melting of Generalized Wigner Crystals in Transition Metal Dichalcogenide Moiré Systems
• Particle-Hole Symmetry and the Reentrant Integer Quantum Hall Wigner Solid
• Unlocking new regimes in fractional quantum Hall effect with quaternions
• Competing Many-Body Phases at Small Fillings in Ultrahigh-Quality GaAs 2D Hole Systems: Role of Landau Level Mixing
• Thermal Activation Signatures of the Anderson Insulator and the Wigner Solid forming near $\nu =1$
• Developing fractional quantum Hall states at $\nu$ = $\frac{1}{7}$ and $\frac{2}{11}$ in the presence of significant Landau level mixing
• Evidence for Topological Protection Derived from Six-Flux Composite Fermions
• Interaction-driven quantum phase transitions between topological and crystalline orders of electrons
• Quantum melting a Wigner crystal into Hall liquids
• Disorder-induced strong-field strong-localization in 2D systems