Magic Numbers of Multivacancy in Crystalline Si: Tight-Binding Studies for the Stability of the Multivacancy

We perform microscopic total-energy calculations based on a transferable tight-binding model combined with conjugate-gradient minimization technique for various multivacancies V n in Si. We find that stable multivacancies (magic numbers of negative Si clusters) are V 6 , V 10 , V 14 , V 17 , V 22 , V 26 and V 35 . We also find that both topological networks of vacant sites and relaxation of surrounding atoms are crucial to determine energetics of the multivacancies.