Fig. S8.

(A) Low energy fits of the $B_{1g}$ response of sample SP208 at 2.33 eV ($532\hspace{0.17em}\mathrm{nm}$) using Eq. S8. Note that the energy range is wider than that of Fig. 4A and Figs. S6A and S7A. (B) Temperature dependences of the inverse of the two contributions to the nematic susceptibility, $A_1$ and $A_2$. The dashed line is a linear fit of $A_1^{-1}$ between $T_{\text{S}}$ and $150\hspace{0.17em}\mathrm{K}$. It crosses the x axis at $T^{*}=31\hspace{0.17em}\mathrm{K}$. (C) Temperature dependences of the line widths ${\mathrm{\Gamma }}_1$ and ${\mathrm{\Gamma }}_2$ of the low and high energy QEPs, respectively. The dashed and dotted lines are linear fits between $T_{\text{S}}$ and $150\hspace{0.17em}\mathrm{K}$. The dashed line crosses the x axis at $T^{\ast \ast }=61\hspace{0.17em}\mathrm{K}$.