Fig. 2: The normalized Raman susceptibility and detailed balance.
From: The range of non-Kitaev terms and fractional particles in α-RuCl3
a Raman susceptibility of RuCl3, \(\Delta {\rm{Im}}[\chi (\omega ,T)]={\rm{Im}}[\chi (\omega ,T)]-{\rm{Im}}[\chi (\omega ,150\,{\rm{K}})]\)). The curves with black outlines are the contour plots of the Fermi function (ΔnF(ω∕2, T) = nF(ω∕2, 150) − nF(ω∕2, T)). Both data and the prediction are normalized to their maximum values. The agreement between the two confirms that Raman creates magnetic excitations that are made of pairs of fermions. The upturn of the Raman intensity in the high temperature and low energy range results from thermal fluctuations of the magnetism (quasi-elastic scattering). b Raman susceptibility of a similar magnet, Cr2Ge2Te6, where, opposite to α-RuCl3, ΔIm[χ(ω, T)] is negative and does not match nF(ω∕2, T). c Comparison of nF(ω∕2, T) and \(\Delta {\rm{Im}}[\chi (\omega ,T)]\) of RuCl3 at fixed temperatures. The agreement further confirms the excitations are fermionic. d The excellent agreement between Stokes and anti-Stokes spectra of α-RuCl3 when normalized by the Boltzmann factor demonstrates the absence of laser heating.
