2007/12/12 by Kunie Ishioka, Muneaki Hase, Masahiro Kitajima +4 · 2 citations
Engineering · Materials Science · Physics and Astronomy · #Diamond and Carbon-based Materials Research #Graphene research and applications #Ion-surface interactions and analysis #cond-mat.mtrl-sci #cond-mat.other
paper · pdf · doi:10.1103/physrevb.77.121402
published as Phys. Rev. B 77, 121402(R) (2008) · 4 pages, 4 figures
arxiv created 2007/12/12 · openalex publication_date 2008/03/12 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We report the ultrafast dynamics of the 47.4\phantom\rule0.3em0exTHz 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.