title: Experimental and Ab Initio Ultrafast Carrier Dynamics in Plasmonic Nanoparticles.
abstract: 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.
authors.affiliation: Thomas J. Watson Laboratories of Applied Physics, California Institute of Technology, 1200 East California Boulevard, Pasadena, California 91125, USA.
authors.forename: Ana M
authors.initials: AM
authors.lastname: Brown
authors.affiliation: Joint Center for Artificial Photosynthesis, California Institute of Technology, 1200 East California Boulevard, Pasadena, California 91125, USA.|Department of Materials Science and Engineering, Rensselaer Polytechnic Institute, 110 8th Street, Troy, New York 12180, USA.
authors.forename: Ravishankar
authors.initials: R
authors.lastname: Sundararaman
authors.affiliation: Thomas J. Watson Laboratories of Applied Physics, California Institute of Technology, 1200 East California Boulevard, Pasadena, California 91125, USA.|Joint Center for Artificial Photosynthesis, California Institute of Technology, 1200 East California Boulevard, Pasadena, California 91125, USA.|NG NEXT, 1 Space Park Drive, Redondo Beach, California 90278, USA.
authors.forename: Prineha
authors.initials: P
authors.lastname: Narang
authors.affiliation: The Molecular Foundry, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California 94720, USA.
authors.forename: Adam M
authors.initials: AM
authors.lastname: Schwartzberg
authors.affiliation: Joint Center for Artificial Photosynthesis, California Institute of Technology, 1200 East California Boulevard, Pasadena, California 91125, USA.|Materials and Process Simulation Center, California Institute of Technology, 1200 East California Boulevard, Pasadena, California 91125, USA.
authors.forename: William A
authors.initials: WA
authors.lastname: Goddard
authors.affiliation: Thomas J. Watson Laboratories of Applied Physics, California Institute of Technology, 1200 East California Boulevard, Pasadena, California 91125, USA.|Joint Center for Artificial Photosynthesis, California Institute of Technology, 1200 East California Boulevard, Pasadena, California 91125, USA.
authors.forename: Harry A
authors.initials: HA
authors.lastname: Atwater