Thickness-dependent electron–lattice equilibration in laser-excited thin bismuth films

Electron-lattice energy relaxation in laser-excited thin-film Au-insulator heterostructures studied by ultrafast MeV electron diffraction

“…3 give clear evidence for a dependence of the relaxation rate on film thickness as well as on the number of Au-insulator interfaces. These observations are in agreement with our recent results on thin Bi-films 18 as well as with some of the time-resolved optical studies, 5–7 providing strong support for the concept of a cross-interfacial coupling of hot electrons in the Au-film to interface vibrational modes, 19,20 which for metal-insulator interfaces mainly reside in the substrate.…”

“…Only recently we have applied time-resolved electron diffraction with MeV electron pulses to study the thickness dependence of the electron-lattice energy relaxation in thin Bi-films 18 . Our experiments revealed an increased relaxation speed with decreasing film thickness indicating direct coupling of metal electrons to phonons of the insulating substrate, 19,20 a process believed to be particularly effective as long as electrons and lattice are not in equilibrium 6,21,22 .…”

Coulomb interaction-induced jitter amplification in RF-compressed high-brightness electron source ultrafast electron diffraction

“…Our work on strong Coulomb interaction-induced jitter amplification provides an important guide for RF technique-based ultrashort electron pulse generation and precise control where laser-electron synchronization is needed, such as in free-electron lasers [40], the Thomson scattering x-ray source [41], MeV UED [42,43], keV UED [32,37], and UEM [26]. The jitter-amplification effect can be found in MeV UED [44] and before our work, indicative that the mechanism is unambiguous.…”

Coherent and incoherent structural dynamics in laser-excited antimony

“…We include a dependence of G ep on T e in the numerical optimization process, which we restrict to being linear, G ep (T e ) = G ep,0 + g · T e , as the data quality and the numerical optimization do not allow to fit a more complex dependence. Heat flow into the capping layers is not expected to significantly influence the evolution of the experimentally obtained lattice temperature, as it has been shown in similar experiments that the equilibration with the Si 3 N 4 substrate occurs on delay times of several tens to hundreds of picoseconds 45 , and would mostly be important in very thin films 19 .…”