Dynamical spin structure factors of α-RuCl₃

Honeycomb-lattice magnet α-RuCl₃ is considered to be a potential candidate of realizing Kitaev spin liquid, although this material undergoes a phase transition to the zigzag magnetically ordered state at T _N ∼ 7 K. Quite recently, inelastic neutron-scattering experiments using single crystal α-RuCl₃ have unveiled characteristic dynamical properties. We calculate dynamical spin structure factors of three ab-initio models for α-RuCl₃ with an exact numerical diagonalization method. We also calculate temperature dependences of the specific heat by employing thermal pure quantum states. We compare our numerical results with the experiments and discuss characteristics obtained by using three ab-initio models. (paper)