Lawrence Berkeley National Laboratory
Experimental and Ab Initio Ultrafast Carrier Dynamics in Plasmonic Nanoparticles.
- Author(s): Brown, Ana M
- Sundararaman, Ravishankar
- Narang, Prineha
- Schwartzberg, Adam M
- Goddard, William A
- Atwater, Harry A
- et al.
Published Web Locationhttps://doi.org/10.1103/physrevlett.118.087401
Ultrafast pump-probe measurements of plasmonic nanostructures probe the nonequilibrium behavior of excited carriers, which involves several competing effects obscured in typical empirical analyses. Here we present pump-probe measurements of plasmonic nanoparticles along with a complete theoretical description based on first-principles calculations of carrier dynamics and optical response, free of any fitting parameters. We account for detailed electronic-structure effects in the density of states, excited carrier distributions, electron-phonon coupling, and dielectric functions that allow us to avoid effective electron temperature approximations. Using this calculation method, we obtain excellent quantitative agreement with spectral and temporal features in transient-absorption measurements. In both our experiments and calculations, we identify the two major contributions of the initial response with distinct signatures: short-lived highly nonthermal excited carriers and longer-lived thermalizing carriers.