Structural Preablation Dynamics of Graphite Observed by Ultrafast Electron Crystallography
By means of time-resolved electron crystallography, we report direct observation of the structural dynamics of graphite, providing new insights into the processes involving coherent lattice motions and ultrafast graphene ablation. When graphite is excited by an ultrashort laser pulse, the excited carriers reach their equilibrium in less then one picosecond by transferring heat to a subset of strongly coupled optical phonons. The time-resolved diffraction data show that on such a time scale the crystal undergoes a contraction whose velocity depends on the excitation fluence. The contraction is followed by a large expansion which, at sufficiently high fluence, leads to the ablation of entire graphene layers, as recently predicted theoretically.
Additional Information© 2008 The American Physical Society. (Received 15 October 2007; published 22 January 2008) This work was supported by the National Science Foundation and by the Gordon and Betty Moore center for physical biology at Caltech. F. Carbone would like to thank the Swiss National Science Foundation, and also A.B. Kuzmenko for stimulating discussions. The authors thank Professor Marlina A. Elburg and Dr. S.L. Molodtsov for providing the raw crystals.
ErrataErratum: Structural Preablation Dynamics of Graphite Observed by Ultrafast Electron Crystallography [Phys. Rev. Lett. 100, 035501 (2008)] Fabrizio Carbone, Peter Baum, Petra Rudolf, and Ahmed H. Zewail Phys. Rev. Lett. 106, 139901
Published - CARprl08.pdf
Erratum - PhysRevLett.106.139901.pdf