P.C. Pattnaik, D.M. Newns
Physical Review B
Conductance measurements between two superconducting electrodes with different gap energies Δ1 and Δ2 were performed with a low-temperature scanning tunneling microscope. The temperature dependence and tip-sample distance dependence of the spectra show a pronounced subgap structure which is interpreted as multiple Andreev reflections (MARs). Low temperature conductance peaks not seen in symmetric superconducting tunnel junctions arise at energies ± Δ1 - Δ2 when the superconducting gaps are sufficiently different. We propose an explanation of these findings by extending the full counting statistics of MARs to describe these asymmetric junctions. © 2006 The American Physical Society.
P.C. Pattnaik, D.M. Newns
Physical Review B
T.N. Morgan
Semiconductor Science and Technology
A. Ney, R. Rajaram, et al.
Journal of Magnetism and Magnetic Materials
A. Gupta, R. Gross, et al.
SPIE Advances in Semiconductors and Superconductors 1990