Roman Shayduk, Marc Herzog, Andre Bojahr, Daniel Schick, Peter Gaal, Wolfram Leitenberger, Hengameh Navirian, Mathias Sander, Jevgenij Goldshteyn, Ionela Vrejoiu, Matias Bargheer
- We synthesize sub-THz longitudinal quasimonochromatic acoustic phonons in a SrTiO3 single crystal using a SrRuO3/SrTiO3 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 k-vector dependent phonon lifetime. It is observed that even at sub-THz frequencies the phonon lifetime agrees with the 1/omega(2) power law known from Akhiezer's model for hyper sound attenuation. The observed shift of the synthesized spectrum to the higher q is discussed in the framework of nonlinear effects appearing due to the high amplitude of the synthesized phonons.
