Roman Shayduk, Jörg Hallmann, Angel Rodriguez-Fernandez, Markus Scholz, Wei Lu, Ulrike Bösenberg, Johannes Möller, Alexey Zozulya, Man Jiang, Ulrike Wegner, Radu-Costin Secareanu, Guido Palmer, Moritz Emons, Max Lederer, Sergey Volkov, Ionela Lindfors-Vrejoiu, Daniel Schick, Marc Herzog, Matias Bargheer, Anders Madsen
- We report generation of ultra-broadband longitudinal acoustic coherent phonon wavepackets in SrTiO3 (STO) with frequency components extending throughout the first Brillouin zone. The wavepackets are efficiently generated in STO using femtosecond infrared laser excitation of an atomically flat 1.6 nm-thick epitaxial SrRuO3 film. We use femtosecond x-ray diffraction at the European X-Ray Free Electron Laser Facility to study the dispersion and damping of phonon wavepackets. The experimentally determined damping constants for multi-THz frequency phonons compare favorably to the extrapolation of a simple ultrasound damping model over several orders of magnitude.