Issue
EPL
Volume 88, Number 5, December 2009
Article Number 57003
Number of page(s) 6
Section Condensed Matter: Electronic Structure, Electrical, Magnetic and Optical Properties
DOI http://dx.doi.org/10.1209/0295-5075/88/57003
Published online 10 December 2009
EPL, 88 (2009) 57003
DOI: 10.1209/0295-5075/88/57003

Resonant spin transport through a superconducting double-barrier structure

Arijit Kundu, Sumathi Rao and Arijit Saha

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

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

received 19 June 2009; accepted in final form 10 November 2009; published December 2009
published online 10 December 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 T = 1/4 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 T = 1. We also point out as an application that the resonant value of T = 1/4 can produce pure spin current through the superconducting double-barrier structure.

PACS
73.23.-b - Electronic transport in mesoscopic systems.
74.45.+c - Proximity effects; Andreev effect; SN and SNS junctions.
72.25.Ba - Spin polarized transport in metals .

© EPLA 2009