Currentcurrent correlations in hybrid superconducting and normalmetal multiterminal structures
Abstract
We consider a hybrid system consisting of two normal metal leads weakly connected to a superconductor. Currentcurrent correlations of the normal leads are studied in the tunneling limit at subgap voltages and temperatures. We find that only two processes contribute to the crosscorrelation: the crossed Andreev reflection (emission of electrons in different leads) and the elastic cotunneling. Both processes are possible due to the finite size of the Cooper pair. Noise measurements can thus be used to probe directly the superconducting wave function without the drawbacks appearing in average current measurements where the current is dominated by direct Andreev reflection processes. By tuning the voltages it is possible to change the sign of the crosscorrelation. Quantitative predictions are presented both in the diffusive and ballistic regimes.
 Publication:

EPL (Europhysics Letters)
 Pub Date:
 July 2004
 DOI:
 10.1209/epl/i2003102939
 arXiv:
 arXiv:condmat/0310349
 Bibcode:
 2004EL.....67..110B
 Keywords:

 Condensed Matter  Mesoscopic Systems and Quantum Hall Effect
 EPrint:
 7 pages, 2 Figures