Phase fluctuations in a strongly disordered s-wave superconductor close to the metal-insulator transition

Mintu Mondal; Anand Kamlapure; Madhavi Chand; Garima Saraswat; Sanjeev Kumar; John Jesudasan; L. Benfatto; Vikram Tripathi; Pratap Raychaudhuri

doi:10.1103/physrevlett.106.047001

arXiv · 1006.4143

Phase fluctuations in a strongly disordered s-wave superconductor close to the metal-insulator transition

Mintu Mondal·Anand Kamlapure·Madhavi Chand·Garima Saraswat·Sanjeev Kumar·John Jesudasan·L. Benfatto·Vikram Tripathi·Pratap Raychaudhuri

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Abstract

We explore the role of phase fluctuations in a 3-dimensional s-wave superconductor, NbN, as we approach the critical disorder for the destruction of the superconducting state. Scanning tunneling spectroscopy measurements reveal that in the presence of strong disorder, a finite gap in the electronic spectrum continues to persist at temperatures above Tc. With increase in disorder, the superfluid density is strongly suppressed at low temperatures and evolves towards a linear-T variation at higher temperatures. These observations provide strong evidence that phase fluctuation leads to the formation of a pseudogap state in a disordered conventional superconductor.

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Mintu Mondal, Anand Kamlapure, Madhavi Chand, Garima Saraswat, Sanjeev Kumar, John Jesudasan, L. Benfatto, Vikram Tripathi, Pratap Raychaudhuri. 2010-11-15. Phase fluctuations in a strongly disordered s-wave superconductor close to the metal-insulator transition. https://doi.org/10.1103/physrevlett.106.047001

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