Dresden 2017 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 100: Electronic Structure of Surfaces: Spectroscopy, Surface States II

O 100.8: Vortrag

Donnerstag, 23. März 2017, 17:45–18:00, WIL C307

Quantum well states and their coupling to phonons in thin multilayer Pb films on Si(111) — •Maedeh Zahedifar and Peter Kratzer — University of Duisburg-Essen, Lotharstr. 1, 47057 Duisburg, Germany

The relaxation of electrons in metals far away from equilibrium constitutes a field of research that has attracted considerable attention recently. Moreover, thin metallic films on semiconductor substrates lend themselves to the study of quantum size effects in metals. In our work, we attempt to develop a sound basis for the investigation of electronic relaxation processes in atomically thin Pb layers by working with the √3 × √3 model for film thicknesses between 3 and 6 ML. Density functional theory calculations with the projector augmented-wave method using the software package VASP [1] are employed to obtain both the electronic and the phononic two-dimensional band structure of these films. Subsequently, the strength of the electronic-phonon coupling is investigated for some representative (either occupied or unoccupied) quantum well states in the four-layer and five-layer Pb films. The results are compared to experimental data of the energetic position, dispersion and lifetime broadening of quantum well states.

[1]G. Kresse and D. Joubert, Phys. Rev. B, 59, (1999).