Thermodynamic perspective on the field-induced behavior of \alpha-RuCl3*

Recent efforts in the search for an experimental realization of the Kitaev quantum spin liquid culminated in the observation of quantized thermal Hall effect in \alpha-RuCl3. We inspect thermodynamics of this material in the relevant range of temperatures and magnetic fields. Our data exclude a separate spin-liquid phase and rule out Kitaev spin liquid as a ground state of \alpha-RuCl3, but indicate the presence of competing proximate phases. We put forward Grueneisen parameters as a sensitive experimental probe of this phase competition that will find applications across the field of frustrated magnetism and beyond.
S. Bachus, D.A.S. Kaib, Y. Tokiwa, A. Jesche, V. Tsurkan, A. Loidl , S.M. Winter, A.A. Tsirlin, R. Valentí and P. Gegenwart, Phys. Rev. Lett. 125, 097203 (2020)