Long-lived nonequilibrium phonons in twisted Van der Waals heterostructures
Ultrafast electron diffraction (UED) measurements on twisted WSe2/MoSe2 heterobilayers reveal that zone-edge M-point phonons retain polarized, non-thermal populations with decay constants nearly twice the monolayer value. To uncover the microscopic scattering pathways governing these lifetimes, we developed a first-pri...