Condensed Matter and Biological Physics Seminars

To test the limits of superconductivity in one dimension we have fabricated a series of ultrathin homogeneous Nb and MoGe wires with diameters below ~10 nm using suspended carbon nanotube as templates. I will describe the fabrication procedure, atomic structure of nanowires and will focus on transport measurements. With decreasing diameter, nanowires display clear superconductor – insulator transition (SIT). In superconducting state, the nanowire resistance was found to follow the classical theory of thermally activated phase slips. In insulating state, zero-bias anomaly and temperature dependence of conductance are well described by the theory of weak Coulomb blockade of coherent single-electron transport. Within this interpretation a nanowire, which in our experiment is shorter than dephasing length, acts as a tunneling junction separating two electrodes.