Dresden 2020 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 59: Correlated Electrons: Quantum Impurities and Kondo Physics; Other Materials

TT 59.11: Talk

Thursday, March 19, 2020, 17:45–18:00, HSZ 03

Zeeman spin-orbit coupling and magnetic quantum oscillations in an antiferromagnetic organic metal — Florian Kollmannsberger^1,2, Michael Kunz^1,2, Werner Biberacher¹, Pavel Grigoriev³, Revaz Ramazashvili⁴, Hideki Fujiwara⁵, and •Mark Kartsovnik¹ — ¹Walther-Meißner-Institut, Garching, Germany — ²Technische Universität München, Garching, Germany — ³L. D. Landau Institute for Theoretical Physics, Chernogolovka, Russia — ⁴Laboratoire de Physique Théorique, Université de Toulouse, Toulouse, France — ⁵Osaka Prefecture University, Osaka, Japan

We employ the layered organic antiferromagnetic (AF) superconductor κ-(BETS)₂FeBr₄ as an exemplary system for revealing theoretically predicted [1] Zeeman spin-orbit coupling (SOC). This novel type of SOC has been proposed as a generic feature of antiferromagnetic metals producing several unusual effects. In particular, it should lead to spin degeneracy of Landau levels, which can be probed by magnetic quantum oscillations [2]. To this end, we have carried out detailed studies of the magnetic quantum oscillations in the low-field, AF, as well as in the high-field, paramagnetic (PM) states of κ-(BETS)₂FeBr₄. We have found that the spin-splitting effect on the oscillation amplitude, observed in the PM state, completely disappears in the AF state [3]. We interpret this result as a direct signature of the Zeeman SOC.

[1] R. Ramazashvili, Phys. Rev. Lett. 101, 137202 (2008).

[2] V.V. Kabanov et al., Phys. Rev. B 77, 132403 (2008).

[3] R. Ramazashvili et al., arXiv:1908.01236 (2019).