Spin injection into a short DNA chain

TL;DR

This study investigates quantum spin transport in a short DNA chain connected to ferromagnetic electrodes, revealing how bias voltage and spin-flip mechanisms influence magnetoresistance.

Contribution

It introduces a realistic tight-binding model for DNA spin transport and analyzes the effects of bias voltage and spin-flip coupling on magnetoresistance.

Findings

Magnetoresistance is below 10% at <4 V bias for 30-basepair DNA.

Magnetoresistance can reach up to 20% at 5 V bias.

Spin-flip mechanisms cause oscillatory behavior in magnetoresistance.

Abstract

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.