Low-energy phonons and superconductivity in Sn$_{.8}$In$_{.2}$Te*

We present neutron scattering measurements on low-energy phonons from a superconducting ($Tc =$ 2.7 K) Sn$_{.8}$In$_{.2}$Te single crystal sample. The longitudinal acoustic phonon mode and one transverse acoustic branch have been mapped out around the (002) Bragg peak for temperatures of 1.7 K and 4.2 K. We observe a substantial energy width of the transverse phonons at energies comparable to twice the superconducting gap; however, there is no change in this width between the superconducting and normal states. We also confirm that the compound is well ordered, with no indications of structural instability.