Evidence of gate-tunable topological excitations in two-dimensional electron systems

Koushik, R and Baenninger, Matthias and Narayan, Vijay and Mukerjee, Subroto and Pepper, Michael and Farrer, Ian and Ritchie, David A and Ghosh, Arindam (2011) Evidence of gate-tunable topological excitations in two-dimensional electron systems. In: Physical Review B: Condensed Matter and Materials Physics, 83 (8).

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Abstract

We report experimental observations of a new mechanism of charge transport in two-dimensional electron systems (2DESs) in the presence of strong Coulomb interaction and disorder. We show that at low enough temperature the conductivity tends to zero at a nonzero carrier density, which represents the point of essential singularity in a Berezinskii-Kosterlitz-Thouless-like transition. Our experiments with many 2DESs in GaAs/AlGaAs heterostructures suggest that the charge transport at low carrier densities is due to the melting of an underlying ordered ground state through proliferation of topological defects. Independent measurement of low-frequency conductivity noise supports this scenario.

Item Type:	Journal Article
Publication:	Physical Review B: Condensed Matter and Materials Physics
Publisher:	The American Physical Society
Additional Information:	Copyright of this article belongs to The American Physical Society.
Department/Centre:	Division of Physical & Mathematical Sciences > Physics
Date Deposited:	08 Mar 2011 06:38
Last Modified:	08 Mar 2011 06:38
URI:	http://eprints.iisc.ac.in/id/eprint/35882

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