Andreev Reflection and Pair Breaking Effects at the Superconductor/Magnetic Semiconductor Interface
Abstract
We investigate the applicability of spin polarization measurements using Andreev reflection in a point contact geometry in heavily doped dilute magnetic semiconductors, such as (Ga,Mn)As. While we observe conventional Andreev reflection in non-magnetic (Ga,Be)As epilayers, our measurements indicate that in ferromagnetic (Ga,Mn)As epilayers with comparable hole concentration the conductance spectra can only be adequately described by a broadened density of states and a reduced superconducting gap. We suggest that these pair-breaking effects stem from inelastic scattering in the metallic impurity band of (Ga,Mn)As and can be explained by introducing a finite quasiparticle lifetime or a higher effective temperature. For (Ga,Mn)As with 8% Mn concentration and 140 K Curie temperature we evaluate the spin polarization to be 83+/-17%. PACS numbers: 72.25.Dc,72.25.Mk,74.45.+c
Cite
@article{arxiv.cond-mat/0502536,
title = {Andreev Reflection and Pair Breaking Effects at the Superconductor/Magnetic Semiconductor Interface},
author = {R. P. Panguluri and K. C. Ku and T. Wojtowicz and X. Liu and J. K. Furdyna and Y. B. Lyanda-Geller and N. Samarth and B. Nadgorny},
journal= {arXiv preprint arXiv:cond-mat/0502536},
year = {2009}
}