Dresden 2009 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 6: Electronic structure I

O 6.1: Vortrag

Montag, 23. März 2009, 11:15–11:30, SCH A216

Electron Dynamics of Quantum-Well States in Pb Nanocrystals — •I-Po Hong, Christophe Brun, François Patthey, and Wolf-Dieter Schneider — École Polytechnique Fédérale de Lausanne, Institut de Physique des Nanostructures, CH-1015 Lausanne, Switzerland

Electrons confined in a thin metal film occupy discrete electronic eigenstates known as quantum well states (QWS). As a function of film thickness, the electronic density of states is modulated in an oscillatory manner when a QWS passes through the Fermi level, affecting many of the physical and chemical properties of a thin film. Here we use low-temperature scanning tunneling microscopy and scanning tunneling spectroscopy to study the quasiparticle linewidth of the QWS in Pb nanocrystals on Si(111)-7×7 and on Pb-√3×√3/Si(111). An analysis of the QWS linewidth within a model which accounts for the tunneling process and electron reflection at the Pb-Si and Pb-vacuum interfaces, allows us to determine quantitatively the QWS quasiparticle lifetime, including defect and interface scattering, electron-phonon interaction, and electron-electron interaction.

We acknowledge financial support of the Swiss National Science Foundation.