Potential energy of two structures of Σ = 11〈0 1 1〉 tilt grain boundary in silicon and germanium with empirical potentials and tight-binding methods

Abstract Two atomic structures A and B of the Σ = 11〈0 1 1〉 grain boundary were observed in silicon and germanium. We have performed a complete study of the stability of these two grain boundaries using some empirical potentials and also the semiempirical, tight-binding (TB) method. The TB method has confirmed the experimental observations at low temperatures. The A structure is more stable in silicon whereas for germanium the B structure is obtained. The empirical potentials, such as those of Keating (1966), Baraff et al. (1980) and of Stillinger and Weber (1985), give the A structure as the most stable for both germanium and silicon. The non-ability of these empirical potentials to make a difference between germanium and silicon and the advantage of TB method are discussed.