Interference of phonon echoes in a nanophononic membrane

The periodic nanostructuration of nanophononic materials can lead to phonon interference and modify their dispersions. EUV transient grating studies in a low-roughness nanoporous phononic membrane of SiN surprisingly reveal that the frequencies are not modified much but the lifetime is strongly reduced. The energy transport, instead, is preserved by the flow among the coherent modes created by the reflections off the nanopores. This effect could be used to tune transport properties of nanostructures. 

The effect of echoes interference on phonon attenuation in a nanophononic membrane
Hadi M., Luo H., Pailhès S., Tanguy A., Gravouil A., Capotondi F., De Angelis D., Fainozzi D., Foglia L., Mincigrucci R., Paltanin E., Pedersoli E., Pelli-Cresi J.S., Bencivenga F., Giordano V.M.
Nature Communications, Vol. 15 - 1, 1317 (2024)