SKM 2021 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 9: Poster Session: Correlated Electrons
TT 9.17: Poster
Dienstag, 28. September 2021, 13:30–16:00, P
Spin-phonon interaction and tunnel splitting in single-molecule magnets — •Kilian Irländer1, Jürgen Schnack1, and Heinz-Jürgen Schmidt2 — 1Fakultät für Physik, Universität Bielefeld, Postfach 100131, Bielefeld D-33501, Germany — 2Fachbereich Physik, Universität Osnabrück, Osnabrück D-49069, Germany
Quantum tunneling of the magnetization is a phenomenon that impedes the use of small anisotropic spin systems for storage purposes even at the lowest temperatures.
Phonons, usually considered for temperature dependent relaxation of magnetization over the anisotropy barrier, also contribute to magnetization tunneling for integer spin quantum numbers.
In this context, it is not viable to consider phonons perturbatively but to treat spins and phonons on the same footing by performing quantum calculations of a Hamiltonian where the single-ion anisotropy tensors are coupled to harmonic oscillators.
We demonstrate the ability of phonons to induce a tunnel splitting of the ground doublet which then reduces the required bistability due to Landau-Zener tunneling of the magnetization [Phys. Rev. B 102, 054407].
We also present the unexpected observation that certain spin-phonon Hamiltonians are robust against the opening of a tunneling gap, even for strong spin-phonon coupling. The key to understanding this phenomenon is provided by an underlying supersymmetry that involves both spin and phonon degrees of freedom.
[1] Eur. Phys. J. B 94, 68