M. Breusing, C. Ropers, T. Elsaesser:

Phys. Rev. Lett. 102, 086809 (2009)

 

Abstract:

Optical pump-probe spectroscopy with 7-fs pump pulses and a probe spectrum wider than 0.7 eV reveals the ultrafast carrier dynamics in freestanding thin graphite films. We discern for the first time a rapid intraband carrier equilibration within 30 fs, leaving the system with separated electron and hole chemical potentials. Phonon-mediated intraband cooling of electrons and holes occurs on a 100 fs time scale. The kinetics are in agreement with simulations based on Boltzmann equations