Dresden 2020 – scientific programme
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MA: Fachverband Magnetismus
MA 14: General Spintronics
MA 14.2: Talk
Monday, March 16, 2020, 15:15–15:30, HSZ 401
Modelling phonon-driven spin-relaxation in organic semiconductors from first-principles — •Uday Chopra1,2, Sergei Egorov1,3, Jairo Sinova1, and Erik R. McNellis1 — 1Johannes Gutenberg University, Staudingerweg 7, Mainz, 55128 — 2Max Planck Graduate Centre, Mainz, Germany — 3University of Virginia, Chemistry Department, McCormick Rd, Charlottesville, VA 22901 USA
Spin-orbit coupling (SOC) is one of the major causes of spin-relaxation in organic semiconductors. As SOC itself does not conserve energy, relaxation is caused in conjunction with external factors, for example a hopping driven spin-flip mechanism [1,2]. In this work, we explore local and non-local spin-relaxation caused due to molecular vibrations. We present a model to estimate the spin-phonon couplings using finite-differences within harmonic approximation from a first-principles approach. Using these couplings we are able to derive the spin-relaxation times (T1) between the Zeeman energy levels for Raman-like processes using Fermi’s Golden rule. Our model assumes a relaxation mediated via two phonons via an intermediate state. This enables us to analyse the relevant phonon-modes that dominate the relaxation in addition to evaluating the temperature dependence of T1. We present our findings using organic-semiconductors and single-molecule magnets to demonstrate transferability across different systems. [1] Chopra et al. Phys. Rev. B 100, 134410 (2019) [2] Chopra et al. J. Phys. Chem. C 123, 19112, (2019)