1. Femtosecond phase-transition in hard x-ray excited bismuth
- Author
-
Makita, M., Vartiainen, I., Mohacs, I., Caleman, C., Diaz, A., Jönsson, H. O., Juranić, P., Medvedev, N., Meents, A., Mozzanica, A., Opara, N., Padeste, C., Panneels, V., Saxena, V., Sikorski, M., Song, S., Vera, L., Willmott, P. R., Beaud, P., Milne, C. J., Ziaja-Motyka, B., and David, C.
- Subjects
Condensed Matter - Materials Science - Abstract
The evolution of the bismuth crystal structure upon excitation of its A$_{1g}$ phonon has been intensely studied with short pulse optical lasers. Here we present the first-time observation of a hard x-ray induced ultrafast phase transition in a bismuth single crystal, at high intensities (~$10^{14}$ W/cm$^2$). The lattice evolution was followed using a recently demonstrated x-ray single-shot probing setup. The time evolution of the (111) Bragg peak intensity showed strong dependence on the excitation fluence. After exposure to a sufficiently intense x-ray pulse, the peak intensity dropped to zero within 300fs, i.e. faster than one oscillation period of the A1g mode at room temperature. Our analysis indicates a nonthermal origin of a lattice disordering process, and excludes interpretations based on electron-ion equilibration process, or on thermodynamic heating process leading to a plasma formation., Comment: Main text 10 pages, 3 figures. Appendix 3 pages, 2 figures
- Published
- 2018