Atomic vibrations on the alpha-Sn(001)(2x1) surface investigated by a linear response scheme and an adiabatic bond-charge model

Abstract

The atomic geometry on the alpha-Sn(001)(2x1) surface have been studied by applying the ab initio pseudopotential method. Using the relaxed geometry, we studied atomic vibrations on this surface by employing two different theoretical methods: a linear response approach based on the density functional theory, and an adiabatic bond-charge model. The results from the two methods compare well with each other. Using the present results, together with previously obtained results for the (001)(2x1) surface of C, Si, and Ge, we have established a few interesting trends across IV(001) surfaces: correlation between dimer length and dimer tilt; correlation between dimer tilt and its strength; and variation of dimer twist phonon mode with the reduced mass and lattice constant.