Relaxation of frequencies and damping of transverse phonons in lead at T = 4.2 K.
Mikhailov Yu.N. , Bobrovski V.I., Goshchitskii B.N., Mirmel'shtein A.V. , Ponosov Yu.S.
We investigated the frequencies and widths of transverse phonons in lead in the [ξξξ] direction at temperatures 4.2, 20.4, 78, and 300°K. At T = 4.2°K we observed softening of the phonons with wave vectors in the interval aq/ΐπ = 0.35-5, and a strong broadening of the single-phonon resonances for ας/2π = 0.5-0.867.