Pulse X-ray photons catch shock-induced lattice deformation in 100 ps time scale

The lattice dynamics of materials under high strain is of great interest in materials science. Japanese scientists led by Professors S. Adachi (KEK, Tsukuba) and S. Koshihara (Tokyo Tech Institute, Tokyo) have recently succeeded in observing the irreversible deformation process of CdS single crystal by single-shot time-resolved Laue diffraction. The time-resolution here is 100 psec, which is a single-bunch X-ray pulse-width, available at the Photon Factory-Advanced Ring (6.5 GeV). The data was obtained with various time delays in the order of nsec. As the observed pattern exhibits six-fold symmetry of the wurtzite structure at 10 ns, corresponding to a shock pressure of 3.92 GPa, i.e., above the threshold pressure of phase transition to a rocksalt structure, they suggest a transient wurtzite structure. For more information, see the paper, "Shock-induced lattice deformation of CdS single crystal by nanosecond time-resolved Laue diffraction", K. Ichiyanagi et al., Appl. Phys. Lett. 91, 231918 (2007).