Fig. 2: Low temperature exciton dispersion and comparison with double-magnons.
From: Magnetically propagating Hund’s exciton in van der Waals antiferromagnet NiPS3
a, b RIXS intensity maps as a function of the H and K in-plane momentum transfer, respectively, with an energy window chosen to isolate the exciton dispersion. The overlaid green squares mark the peak positions of the exciton. c and d show the low energy dispersion at equivalent momenta with the observed inelastic feature, including magnons (white lines) and double-magnons (orange circles). e and f show that the exciton and double-magnon have similar dispersion with an energy offset of ~ 1.4 eV. All the measurements were taken at T = 40 K using π-polarized incident x-rays at an incident energy of 853.4 eV corresponding to the exciton resonance. The asterisks in e and f denote the reported exciton energy from optical measurements4,8,11 with error bars from our instrument energy calibration (one standard deviation). All other error bars are 1-σ confidence intervals evaluated from the fitting as explained in the Methods. Detailed linecuts showing the fitting are provided in Supplementary Figs. 3–5.
