Magnetoresistance of a quantum dot with spin-active interfaces
Abstract
We study the zero-bias magnetoresistance MR of an interacting quantum dot connected to two ferromagnetic leads and capacitively coupled to a gate voltage source Vg. We investigate the effects of the spin-activity of the contacts between the dot and the leads by introducing an effective exchange field in an Anderson model. This spin-activity makes easier negative MR effects, and can even lead to a giant MR effect with a sign tunable with Vg. Assuming a twofold orbital degeneracy, our approach allows to interpret in an interacting picture the MR(Vg) measured by S. Sahoo et al. [Nature Phys. 2, 99 (2005)] in single wall carbon nanotubes with ferromagnetic contacts. If this experiment is repeated on a larger Vg-range, we expect that the MR(Vg) oscillations are not regular like in the presently available data, due to Coulomb interactions.
Cite
@article{arxiv.cond-mat/0605264,
title = {Magnetoresistance of a quantum dot with spin-active interfaces},
author = {Audrey Cottet and Mahn-Soo Choi},
journal= {arXiv preprint arXiv:cond-mat/0605264},
year = {2009}
}
Comments
9 pages, 6 figures, to appear in Phys. Rev. B