Spin-Boson Theory for Magnetotransport in Organic Semiconducting Materials

TL;DR

This paper develops a spin-boson theoretical model to explain organic magnetoresistance by coupling charge carrier spins with a local bosonic environment, highlighting triplet-excitons' role and matching experimental results.

Contribution

It introduces a novel spin-boson framework for magnetotransport in organic semiconductors, emphasizing the importance of triplet-excitons and entanglement in OMR.

Findings

The model reproduces the fundamental behavior of OMR.

OMR depends on bias voltage, spin-boson coupling, and boson frequency.

Results align well with experimental observations.

Abstract

We present a spin-boson theory for magnetotransport in organic semiconducting materials, on the basis of a coupling between charge carriers' spin and a local bosonic environment, which is shown to be an irreducible ingredient in understanding of the anomalous organic magnetoresistance (OMR). Among those composing this environment triplet-excitons play a basic role. The incoherent hopping rate between molecules is calculated to give out the fundamental behavior of OMR. The underlying mechanism is revealed from the calculation of entanglement, represented by the von Neumann entropy, between the carrier's spin and bosons. We also obtain the dependence of OMR on the bias voltage, the spin-boson coupling, and the boson frequency. The results obtained from the theory are in good agreement with experiments.