Quantum Transport with Spin Dephasing: A Nonequilibrium Green's Function Approach

TL;DR

This paper develops a NEGF-based quantum transport model that includes spin dephasing and scattering, providing insights into spin-dependent transport phenomena in magnetic devices.

Contribution

It introduces a unified NEGF framework incorporating spin-flip scattering within the self-consistent Born approximation, applied to magnetic tunnel junctions.

Findings

Spin dephasing significantly affects magnetoresistance.

Small changes in impurity spins cause large resistance variations.

Model aligns well with experimental data.

Abstract

A quantum transport model incorporating spin scattering processes is presented using the non-equilibrium Green's function (NEGF) formalism within the self-consistent Born approximation. This model offers a unified approach by capturing the spin-flip scattering and the quantum effects simultaneously. A numerical implementation of the model is illustrated for magnetic tunnel junction devices with embedded magnetic impurity layers. The results are compared with experimental data, revealing the underlying physics of the coherent and incoherent transport regimes. It is shown that small variations in magnetic impurity spin-states/concentrations could cause large deviations in junction magnetoresistances.