Interplay of thermal and nonthermal effects in x-ray-induced ultrafast melting
Résumé
X-ray laser-induced structural changes in silicon undergoing femtosecond melting have been investigated
by using an x-ray pump–x-ray probe technique. The experiment reveals that the atomic displacements start to
increase at ∼20 fs after the intensity maximum of x-ray pump pulse. By comparing the observed time dependence
of the atomic disordering and the dedicated theoretical simulations, we interpret that the energy transfer from
the excited electrons to ions via electron-ion coupling (thermal effect) as well as a strong modification of the
interatomic potential due to electron excitations (nonthermal effect) trigger the ultrafast atomic disordering. Our
results highlight the need to consider the interplay of thermal and nonthermal effects in the quantitative modeling
of the interaction of intense x rays with matter.
Domaines
Physique [physics]| Origine | Fichiers produits par l'(les) auteur(s) |
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