Time-resolved X-ray diffraction from coherent phonons during a laser-induced phase transition
Publikation/Tidskrift/Serie: Physical Review Letters - Moving Physics Forward
Time-resolved x-ray diffraction with picosecond temporal resolution is used to observe scattering from impulsively generated coherent acoustic phonons in laser-excited InSb crystals. The observed frequencies and damping rates are in agreement with a model based on dynamical diffraction theory coupled to analytic solutions for the laser-induced strain profile. The results are consistent with a 12 ps thermal electron-acoustic phonon coupling time together with an instantaneous component from the deformation-potential interaction. Above a critical laser fluence, we show that the first step in the transition to a disordered state is the excitation of large amplitude, coherent atomic motion.
- Atom and Molecular Physics and Optics
- ISSN: 0031-9007