Decay mechanisms of excited electrons in quantum-well states of ultrathin Pb islands grown on Si(111): Scanning tunneling spectroscopy and theory
Using low-temperature scanning tunneling spectroscopy at 5 and 50 K, we studied the linewidth of unoccupied quantum-well states in ultrathin Pb islands, grown on Si(111) on two different Pb/Si interfaces. A quantitative analysis of the differential conductance spectra allowed us to determine the electron-electron (e-e), electron-phonon (e-ph) and the interface and defect contributions to the lifetime. Layer-dependent ab initio calculations of the e-ph linewidth contribution are in excellent agreement with the data. Importantly, the sum of the calculated e-e and e-ph lifetime broadening follows the experimentally observed quadratic energy dependence.
Keywords: ab initio calculations ; electron-phonon interactions ; elemental semiconductors ; lead ; metallic thin films ; quantum wells ; scanning tunnelling spectroscopy ; silicon ; spectral line broadening ; Surface ; Films ; Microscope ; Lifetime
Record created on 2010-11-30, modified on 2016-08-09