We investigate the dynamical phenomena at the inhomogeneous boundary of an extended atomic well in crystalline solid surfaces. The surfaces are considered as a semi-infinite slab of two coupled atomic layers, and the well as a single atomic chain. This simplified geometric configuration models an atomic well in a surface. The breakdown of translation symmetry in the direction parallel to the surface and normal to the extended well gives rise to localized vibrational modes in its neighborhood. The matching method is used in this study, it may be applied to analyze both the vibrational and the scattering dynamical phenomena for surface inhomogeneities. Characteristic vibrational Green functions and spectral densities are calculated for this system, in particular for the atomic sites which constitute a representative ensemble for the well. The variations of these spectra are presented as a function of the variation of the elastic parameters of the well. This illustrates the variation of the spectra for the softening and the hardening situations of the surface atomic well. The calculated spectra could yield, in comparison with experimental results to come, useful information concerning the elastic parameters of such a surface atomic well.
ASJC Scopus subject areas
- Condensed Matter Physics
- Electronic, Optical and Magnetic Materials