Common features in spin-orbit excitations of Kitaev materials

          @misc{ pirsa_PIRSA:22110065,
            doi = {10.48660/22110065},
            url = {https://pirsa.org/22110065},
            author = {Kim, Young-June},
            keywords = {Condensed Matter},
            language = {en},
            title = {Common features in spin-orbit excitations of Kitaev materials},
            publisher = {Perimeter Institute},
            year = {2022},
            month = {nov},
            note = {PIRSA:22110065 see, \url{https://pirsa.org}}
          }
          

Abstract

"Magnetic materials with 4d or 5d transition metals have drawn much attention for their unique magnetic properties arising from J_eff=1/2 magnetic states. Among them, a honeycomb lattice material with unusual bond-dependent interactions called Kitaev interactions is of particular interest due to the potential for realizing the Kitaev quantum spin liquid state. Although much progress has been made in understanding magnetic and spin-orbit excitations in Kitaev materials, such as Na2IrO3 and alpha-RuCl3, using resonant inelastic X-ray scattering (RIXS), there are still many unanswered questions regarding the nature of electronic excitations in these materials. Of particular interest is the sharp peak observed around 0.4 eV in the RIXS spectrum of Na2IrO3, the exact nature of which remains controversial. In this context, it is interesting to note that a similar lower energy “excitonic” peak was observed in our recent RIXS investigation of alpha-RuCl3. Given that the electronic parameters in alpha-RuCl3 are probably very different from those in Na2IrO3 (alpha-RuCl3 has a large bandgap of ~1eV, well above any SO excitation energy scale), the observed similarity is surprising. The RIXS spectra from these two compounds as well as other Kitaev materials will be compared and the origin of common spectral features will be discussed. "