Fig. 4: FWHM and intensity of the A₁ peak and \(\widetilde{S}=1/2\) excitations.

a, b Ru L₃ RIXS spectra after the correction of x-ray self-absorption effect. The correction to the raw spectra was performed following the procedure in ref. ⁴¹. The blue, green, and dashed black curves exemplify the spectral decomposition into three Voigt profiles representing the quasi-elastic peak, the \(\widetilde{S}=3/2\) transitions (A₁), and the multi-excitons (A₂), respectively. The total fitted curves are shown as thick black lines. c, d The full-width at half maximum (FWHM) of the quasi-elastic and the A₁ peaks as functions of q. e, f Momentum dependence of peak intensities along the q = (H, 0) and (H, H) directions taken at T = 20 K.