Enhancement of the finite-frequency superfluid response in the pseudogap regime of strongly disordered superconducting films

Mintu Mondal, Anand Kamlapure, Somesh Chandra Ganguli, John Jesudasan, Vivas Bagwe, Lara Benfatto, Pratap Raychaudhuri*

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

27 Citations (Scopus)

Abstract

The persistence of a soft gap in the density of states above the superconducting transition temperature T c, the pseudogap, has long been thought to be a hallmark of unconventional high-temperature superconductors. However, in the last few years this paradigm has been strongly revised by increasing experimental evidence for the emergence of a pseudogap state in strongly-disordered conventional superconductors. Nonetheless, the nature of this state, probed primarily through scanning tunneling spectroscopy (STS) measurements, remains partly elusive. Here we show that the dynamic response above T c, obtained from the complex ac conductivity, is highly modified in the pseudogap regime of strongly disordered NbN films. Below the pseudogap temperature, T*, the superfluid stiffness acquires a strong frequency dependence associated with a marked slowing down of critical fluctuations. When translated into the length-scale of fluctuations, our results suggest a scenario of thermal phase fluctuations between superconducting domains in a strongly disordered s-wave superconductor.

Original languageEnglish
Article number1357
JournalScientific Reports
Volume3
DOIs
Publication statusPublished - 11 Mar 2013
MoE publication typeA1 Journal article-refereed

Fingerprint Dive into the research topics of 'Enhancement of the finite-frequency superfluid response in the pseudogap regime of strongly disordered superconducting films'. Together they form a unique fingerprint.

Cite this