Out-of-plane longitudinal sound velocity in SnS₂ determined via broadband time-domain Brillouin scattering

Here, we report time-resolved broadband transient reflectivity measurements performed in a single crystal of SnS₂. We made use of time-domain Brillouin scattering and a broadband probe to measure the out-of-plane longitudinal sound velocity, $υL=(2950±100)ms–1$⁠, in this semiconducting two-dimensional 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 $c33=(39±3)GPa$⁠.