Vibrations of spherical core-shell nanoparticles


The acoustic vibration modes of spherical composite nanoparticles formed by a core and an arbitrary number of shells are computed using a semianalytic approach based on elastic theory. The modes observed in time-resolved pump-probe experiments are identified in the case of metal-dielectric-based spherical composite nanoparticles, and results are illustrated in the case of Ag@SiO2 core-shell nanoparticles. The presence of a light dielectric shell is shown to only weakly shift the frequency of the dominant mode observed in time-resolved experiments. Moreover, a large impact of the mechanical contact between the different materials forming the particle on the vibrational mode frequency and damping is predicted, offering the possibility of experimentally addressing this parameter.

Physical Review B, 83(20) page 205430