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arXiv · 1206.1549

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

Vijay Narayan·Srijit Goswami·Michael Pepper·Jonathan Griffiths·Harvey Beere·Francois Sfigakis·Geb Jones·Dave Ritchie·Arindam Ghosh
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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.

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Vijay Narayan, Srijit Goswami, Michael Pepper, Jonathan Griffiths, Harvey Beere, Francois Sfigakis, Geb Jones, Dave Ritchie, Arindam Ghosh. 2012-08-22. Unconventional Metallicity and Giant Thermopower in a Strongly Interacting Two Dimensional Electron System. https://doi.org/10.1103/physrevb.86.125406

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