Resonant spin transport through a superconducting double-barrier structure

Harish-Chandra Research Institute - Chhatnag Road, Jhusi, Allahabad 211 019, India

Corresponding authors: akundu@mri.ernet.in sumathi@mri.ernet.in arijit.saha@weizmann.ac.il

Received: 19 June 2009
Accepted: 10 November 2009

Abstract

We study resonant transport through a superconducting double-barrier structure. At each barrier, due to the proximity effect, an incident electron can either reflect as an electron or a hole (Andreev reflection). Similarly, transport across the barrier can occur via direct tunneling as electrons as well as via the crossed Andreev channel, where a hole is transmitted. In the subgap regime, for a symmetric double-barrier system (with low transparency for each barrier), we find a new resonance (T is the transmission probability for electrons incident on the double-barrier structure) due to interference between electron and hole wave functions between the two barriers, in contrast to a normal double-barrier system which has the standard transmission resonance at . We also point out as an application that the resonant value of can produce pure spin current through the superconducting double-barrier structure.