Field-angle-resolved specific heat measurements in the Kitaev material α-RuCl<sub>3</sub>
ORAL
Abstract
Recently, 4d5 or 5d5 honeycomb materials with strong spin-orbit coupling have attracted great attention as a candidate for realizing a Kitaev quantum spin liquid (QSL). However, most of the candidate materials show magnetic orders at low temperatures. Indeed, α-RuCl3, one of the most promising candidates, also exhibits a zigzag antiferromagnetic order below TN (~ 7 K). However, the magnetic order of this material can be suppressed by applying a critical magnetic field H* of 7.5 T parallel to the honeycomb plane. Recent thermal transport measurements, as well as spectroscopic studies such as inelastic neutron scattering, suggest the emergence of spin fractionalization into Majorana fermions in the field-induced QSL phase. Here, we report specific heat measurements under in-plane magnetic fields up to 7 T on electron-irradiated α-RuCl3 single crystals, in which a systematic suppression of TN and H* was observed. We find a remarkable six-fold oscillation in the field-angle dependence of the specific heat at low temperatures above H*. This result is consistent with the field-angle dependence of the Majorana gap expected in the Kitaev QSL.
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Presenters
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Ohei Tanaka
- Department of Advanced Materials Science, University of Tokyo
- Univ of Tokyo-Kashiwanoha