Surface lattice-dynamics of the pandey-reconstructed si(111)-2 x 1 - no pathologies in the experimental findings

In this paper we report a slab calculation of the surface phonon dispersion curves for Si(111)-2 × 1 in the framework of the bond charge model dynamics. Our results are in very good agreement with the existing experimental data and provide a comprehensive interpretation for the dynamical structures of this surface, based on the relationships with the unreconstructed one. This "intrinsic" perspective stands in opposition to a recently published analysis, which is grounded on the uniqueness of this surface dynamics, as due to the atomic chains produced by the Pandey reconstruction. The intriguing role of the interface between the 1 × 1 (bulk) and the 2 × 1 (surface) patterns is pointed out in relation to recent EELS measurements and the possibility of exploiting surface characterization via phonon spectroscopy is described. © 1989.