Dichotomy in short superconducting nanowires: Thermal phase slippage vs. Coulomb blockadeA. T. Bollinger, A. Rogachev and A. Bezryadin
Department of Physics, University of Illinois at Urbana-Champaign Urbana, IL 61801-3080, USA
received 12 May 2006; accepted in final form 4 September 2006
published online 27 September 2006
Quasi-one-dimensional superconductors or nanowires exhibit a transition into a nonsuperconducting regime, as their diameter shrinks. We present measurements on ultrashort nanowires (~40-190 long) in the vicinity of this quantum transition. Properties of all wires in the superconducting phase, even those close to the transition, can be explained in terms of thermally activated phase slips. The behavior of nanowires in the nonsuperconducting phase agrees with the theories of the Coulomb blockade of coherent transport through mesoscopic normal metal conductors. Thus it is concluded that the quantum transition occurs between two phases: a "true superconducting phase" and an "insulating phase". No intermediate, "metallic" phase was found.
74.78.Na - Mesoscopic and nanoscale systems.
73.23.Hk - Coulomb blockade; single-electron tunneling.
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