Destruction of superconductivity through phase fluctuations in ultrathin a-MoGe films

Soumyajit Mandal; Surajit Dutta; Somak Basistha; Indranil Roy; John Jesudasan; Vivas Bagwe; Lara Benfatto; Arumugam Thamizhavel; Pratap Raychaudhuri

doi:10.1103/physrevb.102.060501

arXiv · 2003.12398

Destruction of superconductivity through phase fluctuations in ultrathin a-MoGe films

Soumyajit Mandal·Surajit Dutta·Somak Basistha·Indranil Roy·John Jesudasan·Vivas Bagwe·Lara Benfatto·Arumugam Thamizhavel·Pratap Raychaudhuri

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Abstract

We investigate the evolution of superconductivity with decreasing film thickness in ultrathin amorphous MoGe (a-MoGe) films using a combination of sub-Kelvin scanning tunneling spectroscopy, magnetic penetration depth measurements and magneto-transport measurements. We observe that superconductivity is strongly affected by quantum and classical phase fluctuations for thickness below 5 nm. The superfluid density is strongly suppressed by quantum phase fluctuations at low temperatures and evolves towards a linear-T dependence at higher temperatures. This is associated with a rapid decrease in the superconducting transition temperature, Tc, and the emergence of a pronounced pseudogap above Tc. These observations suggest that at strong disorder the destruction of superconductivity follows a Bosonic route where the global superconducting state is destroyed by phase fluctuations even though the pairing amplitude remains finite.

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Soumyajit Mandal, Surajit Dutta, Somak Basistha, Indranil Roy, John Jesudasan, Vivas Bagwe, Lara Benfatto, Arumugam Thamizhavel, Pratap Raychaudhuri. 2020-03-27. Destruction of superconductivity through phase fluctuations in ultrathin a-MoGe films. https://doi.org/10.1103/physrevb.102.060501

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