Josephson Effect due to Odd-frequency Pairs in Diffusive Half Metals
Abstract
The Josephson effect in superconductor / diffusive ferromagnet / superconductor (SFS) junctions is studied using the recursive Green function method in the regime of large exchange energy in a ferromagnet. Motivated by recent experiment [R. S. Keizer, et. al., Nature 439, 825 (2006)] we also address the case of superconductor / diffusive half metal / superconductor junctions. The pairing function in spin-singlet and triplet channels, the Josephson current and their mesoscopic fluctuations are calculated. We show that the spin-flip scattering at the junction interfaces opens the Josephson channel of the odd-frequency spin-triplet Cooper pairs. As a consequence, the local density of states in half metals has a large peak at the Fermi energy. Therefore odd-frequency pairs can be detected experimentally by using the scanning tunneling spectroscopy.
Keywords
Cite
@article{arxiv.cond-mat/0609566,
title = {Josephson Effect due to Odd-frequency Pairs in Diffusive Half Metals},
author = {Yasuhiro Asano and Yukio tanaka and Alexander Golubov},
journal= {arXiv preprint arXiv:cond-mat/0609566},
year = {2015}
}
Comments
5 pages, 4 figures embedded