Moving crystal phases of a quantum Wigner solid in an ultra-high-quality 2D electron system

Abstract

In low-disorder, two-dimensional electron systems (2DESs), the fractional quantum Hall states at very small Landau level fillings ($\nu$) terminate in a Wigner solid (WS) phase, where electrons arrange themselves in a periodic array. The WS is typically pinned by the residual disorder sites and manifests an insulating behavior, with non-linear current-voltage (\textit{I-V}) and noise characteristics. We report here, measurements on an ultra-low-disorder, dilute 2DES, confined to a GaAs quantum well. In the $\nu <1/5$ range, superimposed on a highly-insulating longitudinal resistance, the 2DES exhibits a developing fractional quantum Hall state at $\nu =1/7$, attesting to its exceptional high quality, and dominance of electron-electron interaction in the low filling regime. In the nearby insulating phases, we observe remarkable non-linear \textit{I-V} and noise characteristics as a function of increasing current, with current thresholds delineating three distinct phases of the WS: a pinned phase (P1) with very small noise, a second phase (P2) in which $dV/dI$ fluctuates between positive and negative values and is accompanied by very high noise, and a third phase (P3) where $dV/dI$ is nearly constant and small, and noise is about an order of magnitude lower than in P2. In the depinned (P2 and P3) phases, the noise spectrum also reveals well-defined peaks at frequencies that vary linearly with the applied current, suggestive of washboard frequencies. We discuss the data in light of a recent theory that proposes different dynamic phases for a driven WS.

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Cited by in corpus (12)

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• Evidence of zero-field Wigner solids in ultra-thin films of cadmium arsenide
• Collective depinning and sliding of a quantum Wigner solid in a 2D electron system
• Developing fractional quantum Hall states at even-denominator fillings 1/6 and 1/8
• Quantum melting of generalized electron crystal in twisted bilayer MoSe2
• Competing Many-Body Phases at Small Fillings in Ultrahigh-Quality GaAs 2D Hole Systems: Role of Landau Level Mixing
• Stabilization of a two-dimensional quantum electron solid in perpendicular magnetic fields
• Sliding Dynamics of Current-Driven Skyrmion Crystal and Helix in Chiral Magnets
• Interaction-driven quantum phase transitions between topological and crystalline orders of electrons
• Inequivalence of the low-density insulating state and quantum Hall insulating states in a strongly correlated two-dimensional electron system
• Topological Phase Transitions of Interacting Fermions in the Presence of a Commensurate Magnetic Flux
• Quantum Wigner solid in two-dimensional electron systems in semiconductors