Coherent phonons in Si/ SiGe superlattices
Langue
en
Article de revue
Ce document a été publié dans
Physical Review B: Condensed Matter and Materials Physics (1998-2015). 2007, vol. 75, n° 19, p. 195309
American Physical Society
Résumé en anglais
There are several classes of coherent phonons whose generation mechanisms are completely different: impulsive stimulated Raman scattering, Brillouin oscillations, and coherent longitudinal-acoustic-phonon Bragg reflection. ...Lire la suite >
There are several classes of coherent phonons whose generation mechanisms are completely different: impulsive stimulated Raman scattering, Brillouin oscillations, and coherent longitudinal-acoustic-phonon Bragg reflection. All of these are investigated in Si/ SiGe superlattices using a picosecond ultrasonics technique at room temperature. Bragg reflection for a single vibrational mode is related to gaps in the phonon-dispersion relation at the center and the boundary of the folded Brillouin zone. The two lowest minigaps are observed at 283 and 527 GHz. Theoretical calculations of phonon-dispersion relation and phonon reflection rate are given to explain experimental results.< Réduire
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