Low-Temperature Collapse of Electron Localisation in Two Dimensions

Abstract

We report direct experimental evidence that the insulating phase of a disordered, yet strongly interacting two-dimensional electron system (2DES) becomes unstable at low temperatures. As the temperature decreases, a transition from insulating to metal-like transport behaviour is observed, which persists even when the resistivity of the system greatly exceeds the quantum of resistivity h/e^2. The results have been achieved by measuring transport on a mesoscopic length-scale while systematically varying the strength of disorder.

6 pages, 4 figures To appear in PRL

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• Heat conduction in the disordered Fermi-Pasta-Ulam chain
• Quantum critical transport at a continuous metal-insulator transition
• Unconventional Metallicity and Giant Thermopower in a Strongly Interacting Two Dimensional Electron System
• Evidence of gate-tunable topological excitations in two-dimensional electron systems
• Evidence for mixed phases and percolation at the metal-insulator transition in two dimensions
• Evidence of Novel Quasiparticles in a Strongly Interacting Two-Dimensional Electron System: Giant Thermopower and Metallic Behaviour
• Density-dependent thermopower oscillations in mesoscopic two-dimensional electron gases
• Virtual Scanning Tunneling Microscopy: A Local Spectroscopic Probe of 2D Electron Systems
• Formation of quantum dots in the potential fluctuations of InGaAs heterostructures probed by scanning gate microscopy
• Observation of geometry dependent conductivity in two-dimensional electron systems
• Thermoelectric and electrical transport in mesoscopic two-dimensional electron gases
• 'Metal'-like transport in high-resistance, high aspect ratio two-dimensional electron gases
• Magnetic Field Induced Instabilities in Localised Two-Dimensional Electron Systems
• Anomalous drag in electron-hole condensates with granulated order