Equivalent-crystal theory of metal and semiconductor surfaces and defects

A method is proposed for computing material defect and surface properties accurately at the atomic level. The method is both simple and accurate and treats both semiconductors and metals. Lattice defect and surface energies are determined via perturbation theory on a crystal whose lattice constant is chosen to minimize the perturbation. The energy of the equivalent crystal as a function of its lattice constant is given by a universal energy relation. This simple method is tested via predictions of surface energies, surface reconstructions, and bulk distortions of metals and semiconductors. Good agreement is obtained with the results of both experiment and first-principles calculations.