title: Mechanism of the size dependence of the superconducting transition of nanostructured Nb.
abstract: A direct measurement of the superconducting energy gap by point contact spectroscopy in nanostructured Nb films shows that the gap decreases with a reduction in the average particle size. The superconducting T(c), obtained from transport and magnetic measurements, also decreases with size and scales with the energy gap. The size dependence of the superconducting properties in this intermediate coupling type II superconductor is therefore governed by changes in the electronic density of states rather than by phonon softening. Consistent with the Anderson criterion, no T(c) was observed for sizes below 8 nm.
authors.affiliation: Department of Condensed Matter Physics and Material Science, Tata Institute of Fundamental Research, Mumbai 400005, India.
authors.forename: Sangita
authors.initials: S
authors.lastname: Bose
authors.forename: Pratap
authors.initials: P
authors.lastname: Raychaudhuri
authors.forename: Rajarshi
authors.initials: R
authors.lastname: Banerjee
authors.forename: Parinda
authors.initials: P
authors.lastname: Vasa
authors.forename: Pushan
authors.initials: P
authors.lastname: Ayyub