title: Infrared Absorption and Hot Electron Production in Low-Electron-Density Nanospheres: A Look at Real Systems.
abstract: Doped semiconductor quantum dots are a new class of plasmonic systems exhibiting infrared resonances. At ultralow concentrations of charge carriers that can be achieved by controlled doping, only few carriers occupy each quantum dot; therefore, a spectrum with well-defined atomic-like peaks is expected. Here we investigate theoretically how surface imperfections and inhomogeneities in shape and morphology (surface "roughness") always present in these nanocrystals, randomize their energy levels, and blur the atomic-like features. We assume a Gaussian distribution of each energy level and use their standard deviation σ as a measure of the nanocrystals' roughness. For nearly perfect nanospheres with small roughness (σ), the spectrum exhibits well-defined peaks. However, increasing roughness effectively randomizes the energy level distribution, and when σ approaches 15% of the nanoparticle's Fermi energy, any trace of an atomic-like structure is lost in the spectrum, and a continuous yet few-conduction-electron localized surface plasmon resonance emerges.
authors.affiliation: Departamento de Física Teórica de la Materia Condensada C5 and Condensed Matter Physics Center (IFIMAC), Universidad Autónoma de Madrid , E-28049 Madrid, Spain.
authors.forename: R Carmina
authors.initials: RC
authors.lastname: Monreal
authors.affiliation: Department of Physics and Gothenburg Physics Centre, Chalmers University of Technology , SE-412 96 Göteborg, Sweden.
authors.forename: S Peter
authors.initials: SP
authors.lastname: Apell
authors.affiliation: Department of Physics and Gothenburg Physics Centre, Chalmers University of Technology , SE-412 96 Göteborg, Sweden.|Centre of New Technologies, University of Warsaw , Banacha 2c, 02-097 Warsaw, Poland.
authors.forename: Tomasz J
authors.identifier: http://orcid.org/0000-0003-2535-4174
authors.initials: TJ
authors.lastname: Antosiewicz