Monte Carlo simulation of spin correlations in organic semiconductors with an arbitrary relation between hopping rates and spin dynamics

Abstract

We present a kinetic Monte Carlo (KMC) algorithm designed to study spin correlation phenomena in organic semiconductors including the effect of a magnetic field on electroluminescence and organic magnetoresistance. It allows for an arbitrary relation between hopping rates and spin-precession frequencies, and it incorporates an intermediate averaging procedure to model the spin relaxation within a single KMC simulation run. Our results demonstrate that even a small fraction of hops occurring faster than spin precession can significantly impact the width of the magnetic field dependence of the electroluminescence, which is typically associated with the strength of the hyperfine interaction between electron and nuclear spins. Published by the American Physical Society 2025