| 日時: |
2008-09-01 11:00 - 12:00 |
| 場所: |
４号館２階輪講室１ |
| 会議名: |
放射光セミナー「Femtosecond X-ray Crystallography of Bismuth and Tellurium:Dynamics on the Time Scale of an Optical Phonon Period」 |
| 講演者: |
Dr. Steven Johnson (FEMTO project, Swiss Light Source, Paul Scherrer Institut) |
| 講演言語: |
英語 |
| URL: |
http://pfwww.kek.jp/pf-seminar/ |
| アブストラクト: |
Femtosecond laser excitation of the near-surface region of an optically opaque solid can create unique transient conditions that are far from thermal equilibrium. The properties of the resulting non-equilibrium state can be very different from those of more familiar thermodynamic phases. To
better understand the structural evolution of laser-excited materials, we have used highly asymmetric femtosecond x-ray diffraction to observe the atomic motion in single crystals of bismuth and tellurium on time scales faster than their optical phonon periods. We observe coherent and incoherent structural dynamics that change as a function of distance from the surface of the crystal that give new insights into the electron-phonon interaction in these materials. |
