Resonant tunneling through a small quantum dot coupled to superconducting leads

A. Levy Yeyati, J. C. Cuevas, A. López-Dávalos, A. Martín-Rodero
1997 Physical Review B (Condensed Matter)  
We address the problem of non-linear transport through discrete electronic levels in a small quantum dot coupled to superconducting electrodes. In our approach the low temperature I-V characteristics can be calculated including all multiple quasi-particle and Andreev processes. The limit of very weak coupling to the leads and large charging energies is briefly analyzed comparing the calculated lineshapes of the I-V curves with recent experimental results. When the coupling to the leads
more » ... the leads increases and Coulomb blockade effects can be neglected, the combination of multiple Andreev processes and resonant transmission gives rise to a rich subgap structure which largely differs from the one found in the more studied S-N-S systems. We show how multiple processes can be included within a simple sequential tunneling picture qualitatively explaining the subgap structure. We suggest an experimental set-up where the predicted effects could be observed.
doi:10.1103/physrevb.55.r6137 fatcat:wie6uql6jnb2dmyxnfaf7lv6ke