Phonon-phonon interactions in photoexcited graphite studied by ultrafast electron diffractionстатья
Статья опубликована в высокорейтинговом журнале
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Дата последнего поиска статьи во внешних источниках: 6 мая 2016 г.
Аннотация:We investigated phonon-phonon interactions in photoexcited single-crystalline graphite by ultrafast electron
diffraction. Transient electron diffraction profiles from a 35 nm graphite film were observed following laser
excitation. Changes in intensities of diffraction spots revealed a two-exponential relaxation process with <0.5 ps
and∼8 ps time scales. Furthermore, the transient thermal diffuse scattering signal showed evidence for population
of phonons across the K and M branches of the phonon dispersion spectrum on a <2 ps time scale. Based
on these dynamics, we conclude that the fast relaxation process corresponds to decay of strongly coupled
optical phonons, and the slow relaxation process to redistribution of phonon energy to the equilibrium thermal
distribution.