Resonant inelastic x-ray scattering study of $\alpha$-RuCl${}_3$: a progress report

Abstract

Ru M${}_3$-edge resonant inelastic x-ray scattering (RIXS) measurements of RuCl${}_3$ with 27 meV resolution reveals a spin-orbit exciton without noticeable splitting. We extract values for the spin-orbit coupling constant ($\lambda =154\pm 2$ meV) and trigonal distortion field energy ($\left|\Delta \right|<65$ meV) which support the $j_{\mathrm{eff}}=1/2$ nature of RuCl${}_3$. We demonstrate the feasibility of M-edge RIXS for $4d$ systems, which allows ultra high-resolution RIXS of $4d$ systems until instrumentation for L-edge RIXS improves.