Abstract: | The charge-state-dependent lattice relaxation of mono-vacancy in silicon is studied using the first-principles pseudopotential plane-wave method.We observe that the structural relaxation for the first-neighbor atoms of the mono-vacancy is strongly dependent on its charge state.The difference in total electron density between with and without charge states in mono-vacancy and its relevant change due to the localized positron are also examined by means of first-principles simulation,demonstrating the strong interplay between positron and electron.Our calculations reveal that the positron lifetime decreases with absolute charge value increasing. |