title: Quantum Fluctuations of a Superconductor Order Parameter.
abstract: Tunneling I-V characteristics between very narrow titanium nanowires and "massive" superconducting aluminum were measured. The clear trend was observed: the thinner the titanium electrode, the broader the singularity at eV = Δ1(Al) + Δ2(Ti). The phenomenon can be explained by broadening of the gap edge of the quasi-one-dimensional titanium channels due to quantum fluctuations of the order parameter modulus |Δ2|. The range of the nanowire diameters, where the effect is pronounced, correlates with dimensions where the phase fluctuations of the complex superconducting order parameter Δ = |Δ|e(iφ), the quantum phase slips, broadening the R(T) dependencies, have been observed.
authors.affiliation: National Research University Higher School of Economics, Moscow Institute of Electronics and Mathematics 101000, Moscow, Russia. karutyunov@hse.ru.
authors.forename: K Yu
authors.initials: KY
authors.lastname: Arutyunov
authors.affiliation: VTT Technical Research Centre of Finland Ltd., Centre for Metrology MIKES, P.O. Box 1000, Espoo, FI-02044 VTT, Finland.
authors.forename: J S
authors.initials: JS
authors.lastname: Lehtinen
keywords: Quantum fluctuations; Quasi-one-dimensional superconductivity; Tunneling