Surface Contribution to Thermodynamic Properties of Solids.

We present an approach based on local representation of frequency spectrum to calculate the surface contribution to thermodynamic properties of solids. The Green function theory of isolated point defects is discussed in detail which is also applicable to vibrations of surface atoms. The expression for local spectra of atoms is obtained in terms of the same site Green functions. The surface contribution to thermodynamic properties of solids is expressed in terms of the local frequency spectra of atoms in a few surface layers and the frequency spectrum of the infinite crystal satisfying the cyclic boundary condition. The usefulness of the formulation along with the ability of the recursion method to calculate local spectra without a recourse to detailed frequency calculations of slabs is emphasized. As an illustrative example, we present the surface contribution to low temperature lattice specific heat of tungsten due to (100) surface. [ABSTRACT FROM AUTHOR]