Spin-dependent transport through magnetic nanojunctions

TL;DR

This paper investigates spin-dependent electronic transport in a carbon nanowire molecular device with ferromagnetic electrodes, revealing periodic magnetoresistance variations and potential for use in future spintronic devices.

Contribution

It models spin-dependent transport using NEGF and Hubbard models, showing large TMR effects and oscillatory behavior with wire length and bias voltage.

Findings

Magnetoresistance varies periodically with wire length.

TMR effect can reach tens of percent.

Magnetoresistance oscillates with bias voltage.

Abstract

Coherent electronic transport through a molecular device is studied using non-equilibrium Green's function (NEGF) formalism. Such device is made of a carbon nanowire which is connected to ferromagnetic electrodes. The molecule itself is described with the help of Hubbard model (Coulomb interactions are treated by means of the Hartree-Fock approximation), while the coupling to the electrodes is modeled through the use of a broad-band theory. It was shown that magnetoresistance varies periodically with increasing the length of atomic wire (in the linear response regime) and oscillates with increasing of bias voltage (in the nonlinear response regime). Since the TMR effect for analyzed structures is predicted to be large (tens of percentage), considered junctions seem to be suitable for application as a magnetoresistive elements in the future electronic circuits.