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DY: Dynamik und Statistische Physik

DY 20: Quantum Dynamics I

DY 20.5: Vortrag

Dienstag, 28. März 2006, 10:45–11:00, H\"UL 186

Ultrafast electron dynamics in thin metal films — •Giovanni Manfredi and Paul-Antoine Hervieux — GONLO-IPCMS, 23 rue du Loess, BP 43, F-67034 Strasbourg, France

Self-consistent simulations of the ultrafast electron dynamics in thin metal films were performed using both semiclassical (Vlasov) and quantum (Wigner) phase-space models. Numerical results showed that: (i) heat transport is ballistic and occurs at a velocity close to the Fermi speed; (ii) after the excitation energy has been absorbed by the film, slow nonlinear oscillations appear, with a period proportional to the film thickness, which are attributed to nonequilibrium electrons bouncing back and forth on the film surfaces. These effects are robust and are not suppressed by electron-electron or electron-ion collisions.

When an oscillatory laser field is applied to the film, the field energy is partially absorbed by the electron gas. Maximum absorption occurs when the period of the external field matches the period of the nonlinear oscillations, which, for sodium films, lies in the infrared range. Possible experimental implementations are discussed.