Quantun spin transport through a short DNA chain connected to ferromagnetic electrodes has been investigated by the transfer matrix method. We describe the system by a tight-binding model where the parameters are extracted from the experimental data and realistic metal energy bands. For ferromagnetic iron electrodes, the magnetoresistance of a 30-basepair Poly(G)-Poly(C) DNA is found to be lower than 10% at a bias of < 4 V, but can rach up to 20% at a bias of 5 V. In the presence of the spin-flip mechanism, the magnetoresistance is significantly enhanced when the spin-flip coupling is weak but as the coupling becomes stronger the decreasing magnetoresistance develops an oscillatory behavior.
@article{arxiv.cond-mat/0512473,
title = {Spin injection into a short DNA chain},
author = {X. F. Wang and Tapash Chakraborty},
journal= {arXiv preprint arXiv:cond-mat/0512473},
year = {2009}
}