SKM 2023 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 52: Frustrated Magnets: Strong Spin-Orbit Coupling

TT 52.8: Vortrag

Donnerstag, 30. März 2023, 17:00–17:15, HSZ 201

Phononic-magnetic dichotomy of the thermal Hall effect in the Kitaev-Heisenberg candidate material Na₂Co₂TeO₆ — •Matthias Gillig¹, Xiaochen Hong^2,1, Christoph Wellm¹, Vladislav Kataev¹, Weiliang Yao³, Yuan Li³, Bernd Büchner¹, and Christian Hess^2,1 — ¹Leibniz Institute for Solid State and Materials Research, 01069 Dresden, Germany — ²Fakultät für Mathematik und Naturwissenschaften, Bergische Universität Wuppertal, 42097 Wuppertal, Germany — ³International Center for Quantum Materials, School of Physics, Peking University, 100871 Beijing, China

We investigate the thermal Hall effect of the Kitaev quantum spin liquid candidate material Na₂Co₂TeO₆ in both the magnetically ordered and the paramagnetic phase, with a magnetic field perpendicular to the honeycomb layers of this material. The transversal heat conductivity κ_xy is sizeable, but remains at all temperatures investigated significantly smaller than one half of the thermal conductance quantum which has been predicted as fingerprint of topologically protected Majorana edge modes in a Kitaev quantum spin liquid. κ_xy is negative in the paramagnetic phase but becomes positive deep in the antiferromagnetically ordered phase suggesting a non-phononic origin. However, distinct similarities are present in κ_xy and the longitudinal thermal conductivity κ_xx concerning both their temperature and field dependences. Thus our findings imply an at least two-component, i.e. magnetic and phononic origin of the thermal Hall effect in Na₂Co₂TeO₆.