Unconventional Metallicity and Giant Thermopower in a Strongly Interacting Two Dimensional Electron System

Abstract

We present thermal and electrical transport measurements of low-density (10${}^{14}$ m${}^{-2}$), mesoscopic two-dimensional electron systems (2DESs) in GaAs/AlGaAs heterostructures at sub-Kelvin temperatures. We find that even in the supposedly strongly localised regime, where the electrical resistivity of the system is two orders of magnitude greater than the quantum of resistance $h/e^2$, the thermopower decreases linearly with temperature indicating metallicity. Remarkably, the magnitude of the thermopower exceeds the predicted value in non-interacting metallic 2DESs at similar carrier densities by over two orders of magnitude. Our results indicate a new quantum state and possibly a novel class of itinerant quasiparticles in dilute 2DESs at low temperatures where the Coulomb interaction plays a pivotal role.

8 pages, 8 figures (version to appear in Phys. Rev. B)

References in corpus (3)

• Thermopower of a Kondo-correlated quantum dot
• Low-Temperature Collapse of Electron Localisation in Two Dimensions
• Magnetic field induced Coulomb blockade in small disordered delta-doped heterostructures

Cited by in corpus (11)

• Thermoelectric Effect of Correlated Metals - Band Structure Effects and the Breakdown of Mott's Formula
• Thermoelectricity of cold ions in optical lattices
• Seebeck effects in two-dimensional spin transistors
• Thermoelectricity of Wigner crystal in a periodic potential
• Determining energy relaxation length scales in two-dimensional electron gases
• Au-Ge alloys for wide-range low-temperature on-chip thermometry
• Mesoscopic Diffusion Thermopower in Two-Dimensional Electron Gases
• 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
• Thermoelectric properties of Wigner crystal in two-dimensional periodic potential