Unconventional metallicity and giant thermopower in a strongly interacting two-dimensional electron system

Narayan, Vijay and Pepper, Michael and Griffiths, Jonathan and Beere, Harvey and Sfigakis, Francois and Jones, Geb and Ritchie, Dave and Ghosh, Arindam (2012) Unconventional metallicity and giant thermopower in a strongly interacting two-dimensional electron system. In: PHYSICAL REVIEW B, 86 (12).

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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 localized 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 noninteracting 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.

Item Type:	Journal Article
Publication:	PHYSICAL REVIEW B
Publisher:	AMER PHYSICAL SOC
Additional Information:	Copyright for this article belongs to the American Physical Society
Department/Centre:	Division of Physical & Mathematical Sciences > Physics
Date Deposited:	16 Jan 2013 12:40
Last Modified:	16 Jan 2013 12:40
URI:	http://eprints.iisc.ac.in/id/eprint/45277

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