Rare earth Kitaev materials

We continue the extension of the Kitaev physics and Kitaev interaction to the rare-earth magnets, and study the physical properties of the rare-earth based honeycomb lattice Kitaev materials. We are particularly interested in the experimental consequences of the highly anisotropic spin interaction due to the spin-orbit entanglement. We perform a high-temperature series expansion using a generic nearest-neighbor Hamiltonian with anisotropic interactions, and obtain the heat capacity, the parallel and perpendicular spin susceptibilities, and the magnetic torque coefficients. We further examine the electron spin resonance linewidth as an important signature of the anisotropic spin interactions. Due to the small interaction energy scale of the rare-earth moments, it is experimentally feasible to realize the strong field regime. Therefore, we perform the spin wave analysis and study the possibility of topological magnons when a strong field is applied to the system. The application and relevance to the rare-earth honeycomb Kitaev materials is discussed.