Correlated Conductance Fluctuations Close to the Berezinskii-Kosterlitz-Thouless Transition in Ultrathin NbN Films

Koushik, R and Kumar, Siddhartha and Amin, Kazi Rafsanjani and Mondal, Mintu and Jesudasan, John and Bid, Aveek and Raychaudhuri, Pratap and Ghosh, Arindam (2013) Correlated Conductance Fluctuations Close to the Berezinskii-Kosterlitz-Thouless Transition in Ultrathin NbN Films. In: PHYSICAL REVIEW LETTERS, 111 (19).

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Abstract

We probe the presence of long-range correlations in phase fluctuations by analyzing the higher-order spectrum of resistance fluctuations in ultrathin NbN superconducting films. The non-Gaussian component of resistance fluctuations is found to be sensitive to film thickness close to the transition, which allows us to distinguish between mean field and Berezinskii-Kosterlitz-Thouless (BKT) type superconducting transitions. The extent of non-Gaussianity was found to be bounded by the BKT and mean field transition temperatures and depends strongly on the roughness and structural inhomogeneity of the superconducting films. Our experiment outlines a novel fluctuation-based kinetic probe in detecting the nature of superconductivity in disordered low-dimensional materials.

Item Type:	Journal Article
Publication:	PHYSICAL REVIEW LETTERS
Publisher:	AMER PHYSICAL SOC
Additional Information:	copyright for this article belongs to AMER PHYSICAL SOC USA
Department/Centre:	Division of Physical & Mathematical Sciences > Physics
Date Deposited:	20 Dec 2013 09:42
Last Modified:	20 Dec 2013 09:42
URI:	http://eprints.iisc.ac.in/id/eprint/47953

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