[11a-N401-6~8] 7.4 Buried interface sciences with quantum beam

[11a-N401-6] [Young Scientist Presentation Award Speech] Investigation of Generation Mechanism of Coherent Phonon in Bi with X-Ray Free-Electron Laser

〇Yuya Kubota¹, Yoshikazu Tanaka¹, Tadashi Togashi^2,1, Tomio Ebisu¹, Kenji Tamasaku¹, Hitoshi Osawa², Tetsuya Wada³, Osamu Sugino³, Iwao Matsuda³, Makina Yabashi^1,2 (1.RIKEN, 2.JASRI, 3.ISSP)

Keywords:coherent phonon, X-ray free-electron laser, ultrafast XRD at low temperature

Coherent phonon is a metastable lattice motion excited by ultrashort laser pulses. Although there have been a variety of studies, the origin of coherent phonon is still a matter of debate. To examine this issue, it is essentially important to directly observe the lattice dynamics in a wide temperature range, including cryogenic temperatures. In this study, we developed a system that enables us to perform low-temperature time-resolved X-ray diffraction measurements, which has been difficult in the past. We succeeded in directly observing a temperature dependence of the lattice displacement of Bi, which is a typical material showing coherent phonon.