Stable and Metastable Tetravacancies in an fcc Metal

Abstract

The lattice distortions and relaxation energies around the various compact forms of tetravacancy have been calculated with the aid of a digital computer. A Morse function was used for the interaction energies and the constants corresponding to copper were used. The most stable configuration is that in which the four vacancies lie on a {111} plane forming a rhombus made up of two equilateral triangles with a common side. The binding energy of this configuration is 2.98 eV. The binding energy of the configuration in which the four vacancies form a square on a {100} plane is 2.60 eV, and the tetrahedral arrangement of four vacancies has a binding energy of 0.97 eV. The results are thought to have a bearing on the formation and nature of larger vacancy clusters.