It was shown that the di-vacancy in Si in the diamagnetic doubly negative charge state has a static trigonal symmetry with inward breathing mode lattice relaxation. There was no measurable Jahn-Teller effect, unlike other charge states of the defect. This conclusion was drawn from an analysis of the piezoscopic characteristics of the complex derived from Laplace high-resolution deep-level transient spectroscopy.

Piezoscopic Deep-Level Transient Spectroscopy Studies of the Silicon Divacancy. L.Dobaczewski, K.Gościński, Z.R.Zytkiewicz, K.Bonde Nielsen, L.Rubaldo, O.Andersen, A.R.Peaker: Physical Review B, 2002, 65[11], 113203 (4pp)