Nonequilibrium Electron Interactions in Metal Films

TL;DR

This study investigates ultrafast electron relaxation in silver films, revealing transient increases in energy loss rate and damping linked to the athermal electron state, supported by experimental and simulation data.

Contribution

It provides new insights into the transient electron scattering processes during early thermalization in metal films.

Findings

Electron-gas energy loss rate increases over time.

Free electron damping is enhanced during early thermalization.

Numerical simulations support the experimental observations.

Abstract

Ultrafast relaxation dynamics of an athermal electron distribution is investigated in silver films using a femtosecond pump-probe technique with 18 fs pulses in off-resonant conditions. The results yield evidence for an increase with time of the electron-gas energy loss rate to the lattice and of the free electron damping during the early stages of the electron-gas thermalization. These effects are attributed to transient alterations of the electron average scattering processes due to the athermal nature of the electron gas, in agreement with numerical simulations.