Soft x-rays were applied to induce graphitization of diamond through a non-thermal solid-to-solid phase transition. This process was observed within poly-crystalline diamond with a time-resolved experiment using ultrashort soft x-ray pulses of duration 52.5 fs and cross correlated by an optical pulse of duration 32.8 fs. This scheme enabled for the first time the measurement of a phase transition on a timescale of ~150 fs. Excellent agreement between experiment and theoretical predictions was found, using a dedicated code that followed the non-equilibrium evolution of the irradiated diamond including all transient electronic and structural changes. These observations confirm that soft x-rays can induce a non-thermal ultrafast solid-to-solid phase transition on a hundred femtosecond timescale.
@article{arxiv.1612.06698,
title = {Soft x-rays induce femtosecond solid-to-solid phase transition},
author = {Franz Tavella and Hauke Höppner and Victor Tkachenko and Nikita Medvedev and Flavio Capotondi and Torsten Golz and Yun Kai and Michele Manfredda and Emanuele Pedersoli and Mark Prandolini and Nikola Stojanovic and Takanori Tanikawa and Ulrich Teubner and Sven Toleikis and Beata Ziaja},
journal= {arXiv preprint arXiv:1612.06698},
year = {2017}
}