Spin-flip processes of polarons by magnetic impurities in conjugated polymers

Abstract

By employing an adaptive time-dependent density-matrix-renormalization-group method, the spin-flip process of polarons is investigated in a polymer chain with magnetic impurities. Being driven by an external electric field, a polaron carrying both spin 1/2 and charge +/-e moves at a constant speed in the polymer chain. When the polaron passes through a specific site, which couples to a magnetic impurity via spin-exchange interaction, a spin-flip process is observed if its spin is antiparallel to the impurity spin. Our results show that the spin-flip probability is enhanced by the on-site Coulomb interaction and increases with increase in the spin-exchange integral. Additionally, some possible applications of the spin-state swap between the polaron and the impurity are discussed.

Simulations of polaron spin inversion in an organic semiconductor: Comparison of two mechanisms

“…In real materials, in addition to the SOC and HFI as mentioned above, more factors such as the thermal effect [21] and the scattering of magnetic impurities [22] can also contribute to spin flip in the systems, making the modeling of spin relaxation in organic semiconductors more complicated. Moreover, while spin-dependent polaron hopping in disordered organic semiconductors has been extensively studied, spin relaxation based on polaron drift in organic semiconductors was much less investigated in the literature.…”