Spin triplet states of double donors in silicon.

Forbidden final states for chalcogen double donors in Si have been observed in uniaxial stress studies in which forbidden and allowed final states are stress-tuned into near resonance, The 1s(E) binding energy we determine confirms the previous interpretation of Fano resonance data. Characteristics of spin triplet states are determined for the helium-like double donors and demonstrate the importance of multielectron effects.