Thin films of lead have been grown on the Cu(111) surface and their structure and phonon dispersion curves have been investigated with high-resolution helium atom scattering. The diffraction pattern of the first monolayer (ML) indicates a p(4×4) structure. Films consisting of N=3, 4, 5, and bulklike 50 ML all have a regular (1×1) structure with the same lattice constant as the bulk and small superimposed p(4×4) peaks for the thinnest films. The time-of-flight spectra reveal an unusually large number of inelastic peaks for all the films. The results have been analyzed in terms of dispersion curves which exhibit more than 1 / 2 the total number of expected two N modes active in the planar scattering geometry. Dispersion curves for an unannealed 5 ML film are also reported. A force-constant model fitted to the bulk dispersion curves can only qualitatively reproduce some of the data but help to explain some features. Along the Γ̅ −K̅ direction, a Kohn anomaly is identified for the 3, 4, and 5 ML films at nearly the same wave vector as in the bulk along the equivalent direction.
Braun, J., Ruggerone, P., Zhang, G., Toennies, J.P., & Benedek, G. (2009). Surface phonon dispersion curves of thin Pb films on Cu(111). PHYSICAL REVIEW. B, CONDENSED MATTER AND MATERIALS PHYSICS, 79(20), 205423-1-205423-13.
|Citazione:||Braun, J., Ruggerone, P., Zhang, G., Toennies, J.P., & Benedek, G. (2009). Surface phonon dispersion curves of thin Pb films on Cu(111). PHYSICAL REVIEW. B, CONDENSED MATTER AND MATERIALS PHYSICS, 79(20), 205423-1-205423-13.|
|Tipo:||Articolo in rivista - Articolo scientifico|
|Carattere della pubblicazione:||Scientifica|
|Titolo:||Surface phonon dispersion curves of thin Pb films on Cu(111)|
|Autori:||Braun, J; Ruggerone, P; Zhang, G; Toennies, JP; Benedek, G|
|Data di pubblicazione:||2009|
|Rivista:||PHYSICAL REVIEW. B, CONDENSED MATTER AND MATERIALS PHYSICS|
|Digital Object Identifier (DOI):||http://dx.doi.org/10.1103/PhysRevB.79.205423|
|Appare nelle tipologie:||01 - Articolo su rivista|