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arXiv · 1909.10071

Robust pseudogap across the magnetic field driven superconductor to insulator-like transition in strongly disordered NbN films

Indranil Roy·Rini Ganguly·Harkirat Singh·Pratap Raychaudhuri
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Abstract

We investigate the magnetic field evolution of the superconducting state in a strongly disordered NbN thin film which exhibits a magnetic field tuned superconductor to insulator-like transition, employing low temperature scanning tunneling spectroscopy (STS). Transport measurements of the sample reveals a characteristic magnetic field, which separates the low field state where resistance decreases with decreasing temperature, i.e. dR/dT > 0 and a high-field state where dR/dT < 0. However, STS imaging of the superconducting state reveals a smooth evolution across this field and the presence of a robust pseudogap on both sides of this characteristic field. Our results suggest that the superconductor-insulator transition might be a percolative transition driven by the shrinking of superconducting fraction with magnetic field.

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Indranil Roy, Rini Ganguly, Harkirat Singh, Pratap Raychaudhuri. 2019-09-22. Robust pseudogap across the magnetic field driven superconductor to insulator-like transition in strongly disordered NbN films. https://doi.org/10.1140/epjb/e2019-90488-0

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