Fig. 1: Definitions of distribution relaxation time-scales τH and τE.
We define time-scales τH and τE to characterize two distinct effects of quasiparticle interactions on nonequilibrium electron dynamics. τH measures how quickly electron–electron and electron–phonon interactions redistribute energy from high to low energy electronic states. τE measures how quickly electron–electron and electron–phonon interactions cause energy transfer from the electronic subsystem to the lattice. a After excitation with energy hv, the occupation states where |ε| ≥ hv/2 decays with time τH. Here, we show τH for Au. b The energy absorbed by the electrons remains in the electronic subsystem for time τE. In Au, τE is 35 times greater than τH.
