Spin dephasing in organic semiconductor spintronic devices

Abstract

A theoretical model to study spin dephasing for materials with weak spin orbit coupling is developed in this work. It considers the contributions from not only the drift current but also the diffusion part, which pronouncedly enlarges the application scope of the model. The spin lifetime in spin drift diffusion equation is also corrected by considering the thermal effect and the influence of external electrical field. The spin lifetime corrected by this model agrees well with the experimental data. It is found that under the same voltage bias the spin coherence are much more pronounced in the organic semiconductors (OS) than in Si due to the fact that the applied electrical field affects only part of charge carriers polarons in OS, and a continuous spin transport could be achieved in a larger scale.