Out-of-plane longitudinal sound velocity in SnS${}_2$ determined via broadband time-domain Brillouin scattering

Here we report time-resolved broadband transient reflectivity measurements performed in a single crystal of SnS${}_2$. We made use of time-domain Brillouin scattering and a broadband probe to measure the out-of-plane longitudinal sound velocity $v_L$ = (2950 $\pm$ 100) m s${}^{-1}$, in this semiconducting two-dimensional transition metal dichalcogenide. Our study illustrates the potential of this non-invasive all-optical pump-probe technique for the study of the elastic properties of transparent brittle materials and provides the value of the elastic constant $c_{33}$ = (39 $\pm$ 3) GPa.