Observing spin fractionalization of the Kitaev spin liquid via temperature evolution of the K-edge RIXS response*

A prominent feature of the Kitaev quantum spin liquid is fractionalization of the spin degree of freedom. Here we propose that the temperature evolution of the fractionalization in the Kitaev honeycomb model can be studied by
the resonant inelastic X-ray scattering (RIXS). We calculate the RIXS response of the Kitaev honeycomb model and show how
the momentum-energy map of the fractionalization varies with temperature. We also suggest that the indirect RIXS process at Ru K-edge which allows for sub-meV resolution can provide important insights about the structure of the excitation spectrum in $\alpha$-RuCl$_3$.