Abstract
We synthesize sub-THz longitudinal quasimonochromatic acoustic phonons in a SrTiO single crystal using a SrRuO/SrTiO superlattice as an optical-acoustic transducer. The generated acoustic phonon spectrum is determined using ultrafast x-ray diffraction. The analysis of the generated phonon spectrum in the time domain reveals a -vector dependent phonon lifetime. It is observed that even at sub-THz frequencies the phonon lifetime agrees with the 1/ power law known from Akhiezer's model for hyper sound attenuation. The observed shift of the synthesized spectrum to the higher is discussed in the framework of nonlinear effects appearing due to the high amplitude of the synthesized phonons.
- Received 18 December 2012
DOI:https://doi.org/10.1103/PhysRevB.87.184301
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