Tight-binding electronic theory for lattice defects in transition metals

A tight-binding type electronic theory is used to calculate the atomic relaxation (deltaR/sub i/), formation and binding energies (E/sub fv/ and E/sub bin/) of vacancy-type lattice defects in transition metals. The short-range repulsive energies between atomic sites i and j are simulated by the Born-Mayer potential. An electronic correlation contribution is taken into account using a second-order perturbation theory within the Hubbard model. It is shown that correlation effects play a significant role in determining the physical properties of the lattice defects (deltaR/sub i/, E/sub fv/, and E/sub bin/) in transition metals. This tendency is observed for the lattice defects on the surface as well. (author)