Quantum Wigner solid in two-dimensional electron systems in semiconductors

Abstract

We review recent transport experiments that reveal two-threshold voltage-current characteristics, marked by a significant increase in noise between the two threshold voltages, at low electron densities in the insulating regime in two-dimensional (2D) electron systems, specifically in silicon metal-oxide-semiconductor field-effect transistors (MOSFETs) and SiGe/Si/SiGe heterostructures. The double-threshold voltage-current characteristics closely resemble those observed in the collective depinning of the vortex lattice in type-II superconductors. By adapting the model used for vortices to the case of an electron solid, good agreement with the experimental results is achieved, which supports a quantum electron solid forming in the low electron density state. When a perpendicular magnetic field is applied, the double-threshold behavior occurs at voltages an order of magnitude lower and at significantly higher electron densities than the zero-field case. This indicates the stabilization of the quantum electron solid, aligning with theoretical predictions. Interestingly, the double-threshold voltage-current curves, indicative of electron solid formation at low densities, are not observed in the quantum Hall regime. This lack of observation does not confirm the existence of a quasi-particle quantum Hall Wigner solid and indicates that quasi-particles near integer filling do not form an independent subsystem.

Advances in Physics: X, in press

References in corpus (27)

• Correlation energy and spin polarization in the 2D electron gas
• Sharp increase of the effective mass near the critical density in a metallic 2D electron system
• Correlation lengths of Wigner crystal order in two dimensional electron system at high magnetic field
• Metal-insulator transitions and the effects of electron-electron interactions in two-dimensional electron systems
• Universal Behavior of the Resistance Noise across the Metal-Insulator Transition in Silicon Inversion Layers
• Microwave Resonance of 2D Wigner Crystal around integer Landau fillings
• Competing correlated states around the zero field Wigner crystallization transition of electrons in two-dimensions
• Pauli spin susceptibility of a strongly correlated two-dimensional electron liquid
• Critical Behavior of a Strongly Interacting 2D Electron System
• Evidence of a first order phase transition between Wigner crystal and Bubble Phases of 2D electrons in higher Landau levels
• Observation of pinning mode in Wigner solid of 1/3 fractional quantum Hall excitations
• Ultra-high mobility two-dimensional electron gas in a SiGe/Si/SiGe quantum well
• Transport evidence for a sliding two-dimensional quantum electron solid
• Evidence of a two-stage melting of Wigner solids in two dimensions
• Indication of band flattening at the Fermi level in a strongly correlated electron system
• Anisotropic, two-dimensional, disordered Wigner solid
• Moving crystal phases of a quantum Wigner solid in an ultra-high-quality 2D electron system
• Connecting the Reentrant Insulating Phase and the Zero Field Metal-Insulator Transition in a 2D Hole System
• Microwave spectroscopic observation of distinct electron solid phases in wide quantum wells
• Vortex Washboard Voltage Noise in Type-II Superconductors
• Unusual anisotropy of inplane field magnetoresistance in ultra-high mobility SiGe/Si/SiGe quantum wells
• The Quantum Hall Effect in the Absence of Disorder
• Pinning modes of high magnetic field Wigner solids with controlled alloy disorder
• Collective depinning and sliding of a quantum Wigner solid in a 2D electron system
• Triple-top-gate technique for studying the strongly interacting 2D electron systems in heterostructures
• Stabilization of a two-dimensional quantum electron solid in perpendicular magnetic fields
• Inequivalence of the low-density insulating state and quantum Hall insulating states in a strongly correlated two-dimensional electron system