[en] We report the ultrafast dynamics of the 47.4 THz coherent phonons of graphite interacting with a photoinduced nonequilibrium electron-hole plasma. Unlike conventional materials, upon photoexcitation the phonon frequency of graphite upshifts, and within a few picoseconds relaxes to the stationary value. Our first-principles density functional calculations demonstrate that the phonon stiffening stems from the light-induced decoupling of the nonadiabatic electron-phonon interaction by creating a nonequilibrium electron-hole plasma. Time-resolved vibrational spectroscopy provides a window on the ultrafast nonquilibrium electron dynamics.
Disciplines :
Physics
Author, co-author :
Ishioka, Kunie; National Institute for Materials Science > Advanced Nano-Characterization Center
Hase, Muneaki; National Institute for Materials Science > Advanced Nano-Characterization Center
Kitajima, Masahiro; National Institute for Materials Science > Advanced Nano-Characterization Center
Wirtz, Ludger ; CNRS UMR 8520 > Institute for Electronics, Microelectronics, and Nanotechnology
Rubio, Angel; European Theoretical Spectroscopy Facility, Universidad del País Vasco, Centro Mixto CSIC-UPV/EHU and Donostia International Physics Center
Petek, Hrvoje; Department of Physics and Astronomy, University of Pittsburgh and Donostia International Physics Center
