Effects of Intra- and Interband Transitions on Electron-Phonon Coupling and Electron Heat Capacity After Short-Pulsed Laser Heating

Abstract

This work considers the effects of intra- and direct interband transitions on electron heat capacity and the electron-phonon coupling factor in metals. In the event of an interband transition, the population of the electron bands around the Fermi level will change, affecting the electron density of states and subsequently the thermophysical properties. In the event of photon-induced interband transitions, this repopulation can occur even at relatively low temperatures. This introduces a photon energy-dependent population term into density of states calculations when examining the effects of direct interband transitions on electron heat capacity and the electron-phonon coupling factor in temperature regimes where traditionally only intraband transitions are considered. Example calculations are shown for copper and the two-temperature model is solved using the interband-dependent values of electron heat capacity and electron-phonon coupling factor to examine the effect of these transitions on the transient electron temperature after short-pulsed laser heating.