@article{7611,
  author = {J. Gaudin and O. Peyrusse and J. Chalupsky and M. Toufarova and L. Vysin and V. Hajkova and R. Sobierajski and T. Burian and Dastjani Farahani and A. Graf and M. Amati and L. Gregoratti and S. P. Hau-Riege and G. Hoffmann and L. Juha and J. Krzywinski and R. A. London and S. Moeller and H. Sinn and S. Schorb and M. Stormer and T. Tschentscher and V. Vorlicek and H. Vu and J. Bozek and C. Bostedt},
  title = {Amorphous to crystalline phase transition in carbon induced by intense femtosecond x-ray free-electron laser pulses},
  abstract = {We present the results of an experiment where amorphous carbon undergoes a phase transition induced by femtosecond 830 eV x-ray free-electron laser pulses. The phase transition threshold fluence is found to be 282 +/- 11 mJ/cm(2). Atomic force microscopy, photoelectron microscopy, and micro-Raman spectroscopy give experimental evidence for the phase transition in terms of a volume expansion, graphitization, and change of local order of the irradiated sample area. The interaction is modeled by an accurate time-dependent treatment of the ionization dynamics coupled to a two-temperature model. At the phase transition fluence threshold the free-electron density N-e is found to be at maximum 9 x 10(20) cm(-3) while the ion (atom) temperature is found to be 1050 K, e.g., above the crystallization activation temperature reported in the literature. This low ionization rate and high atom temperature suggest a thermally activated phase transition.},
  year = {2012},
  journal = {Physical Review B},
  volume = {86},
  pages = {024103},
  month = {Jul},
  isbn = {1098-0121},
  doi = {10.1103/PhysRevB.86.024103},
  language = {English},
}