Regensburg 2019 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 53: Frustrated Magnets - Strong Spin-Orbit Coupling (joint session TT/MA)
TT 53.13: Talk
Thursday, April 4, 2019, 12:45–13:00, Theater
Heat transport in the putative Kitaev-Heisenberg spin liquid α-RuCl3 under high magnetic fields — •Matthias Gillig1, Xiaochen Hong1, Richard Hentrich1, Federico Caglieris1, Maryam Shahrokhvand2, Uli Zeitler2, Maria Roslova3, Anna Isaeva3, Thomas Doert3, Bernd Büchner1, and Christian Hess1 — 1Leibniz Institute for Solid State and Material Research Dresden, Germany — 2HFML, Radboud University, Nijmegen, Netherlands — 3Faculty of Chemistry and Food Chemistry, TU Dresden, Germany
α-RuCl3 is due to the honeycomb structure of its Ru-sites and the exchange frustration a prime candidate to realize the Kitaev model in a material. The model bears interesting physics with a quantum spin liquid (QSL) ground state and exotic excitations. Although α-RuCl3 orders antiferromagnetically (AFM) below 7 K, indications of a QSL were found experimentally.
We have performed heat transport measurements on α-RuCl3 down to T = 0.4 K and up to B = 33 T. Below T = 4 K thermal conductivity κ is raised in low magnetic fields up to 5 T before it decreases again to a minimum at 8 T. This decline coincides with the suppression of the AFM phase. For B > 8 T, κ is strongly enhanced for all temperatures and no sign of saturation is observed. The increase of thermal conductivity can be assigned to a field-induced phase featuring a field-dependent excitation spectrum. More specifically the data suggest the opening of a spin excitation gap which reduces the phononic scattering rate. For the whole T- and B-range investigated the data are consistent with a pure phononic heat transport mechanism.