A fourteen-fold anisotropy in the spin transport efficiency parallel and perpendicular to the charge transport is observed in a vertically-biased (Ga,Mn)As-based spin-polarized light emitting diode. The spin polarization is determined by measuring the polarization of electroluminescence from an (In,Ga)As quantum well placed a distance d (20 to 420 nm) below the p-type ferromagnetic (Ga,Mn)As contact. In addition, a monotonic increase from 0.5 to 7% in the polarization is measured as d decreases for collection parallel to the growth direction, while the in-plane polarization from the perpendicular direction (~0.5%) remains unchanged.
@article{arxiv.cond-mat/0201377,
title = {Anisotropic Electrical Spin Injection in Ferromagnetic Semiconductor Heterostructures},
author = {D. K. Young and E. Johnston-Halperin and D. D. Awschalom and Y. Ohno and H. Ohno},
journal= {arXiv preprint arXiv:cond-mat/0201377},
year = {2009}
}
Comments
11 pages, 3 figures, to be published, Applied Physics Letters, March 11, 2002