Surface plasmon in metallic nanoparticles: renormalization effects due to electron-hole excitations

摘要

The electronic environment causes decoherence and dissipation of thecollective surface plasmon excitation in metallic nanoparticles. We show thatthe coupling to the electronic environment influences the width and theposition of the surface plasmon resonance. A redshift with respect to theclassical Mie frequency appears in addition to the one caused by the spill-outof the electronic density outside the nanoparticle. We characterize thespill-out effect by means of a semiclassical expansion and obtain itsdependence on temperature and the size of the nanoparticle. We demonstrate thatboth, the spill-out and the environment-induced shift are necessary to explainthe experimentally observed frequencies and confirm our findings bytime-dependent local density approximation calculations of the resonancefrequency. The size and temperature dependence of the environmental influenceresults in a qualitative agreement with pump-probe spectroscopic measurementsof the differential light transmission.