Starts 11 Dec 2008 11:00
Ends 11 Dec 2008 20:00
Central European Time
Leonardo da Vinci Building Seminar Room
Strada Costiera, 11 I - 34151 Trieste (Italy)
We investigate transport properties of a superconducting junction of one-dimensional quantum wires. We include the effect of electron-electron interaction within the one-dimensional quantum wires using a weak interaction renormalization group (WIRG) procedure. Due to the proximity effect, transport across the junction occurs via direct tunneling as well as via crossed Andreev channel. We find that the fixed point structure of this system is far more rich than the fixed point structure of a normal metal-superconductor (NS) junction, where we only have two fixed points - the fully insulating fixed point or the Andreev fixed point. Even a two wire system with a superconducting junction i.e. a normal metal-superconductor-normal metal (NSN) structure, has non-trivial fixed points with intermediate transmissions and reflections. We demonstrate possible scenarios for production of pure spin current through such junctions and show that there are fixed points in the theory which correspond to the case of pure spin current. We have also shown that (a) effects due to inclusion of electron-electron interaction induced back-scattering in the wire, and (b) competition between the charge transport via the electron and hole channels across the junction give rise to a non-monotonic behavior of subgap conductance as a function of temperature.
  • M. Poropat