The equilibrium structure of ErOn (n < 6) complexes in crystalline Si was investigated by density-functional computations. Two different geometries were considered,

 corresponding to the substitutional and tetrahedral interstitial site for Er. All atomic coordinates were optimized by Car-Parrinello molecular dynamics. The resultant structures have low symmetry, with E-O distances of about 0.235nm. The substitutional site was the most stable one for n below 2, while the tetrahedral interstitial was favored for n greater than 2.

Equilibrium Structure of Erbium-Oxygen Complexes in Crystalline Silicon. A.G.Raffa, P.Ballone: Physical Review B, 2002, 65[12], 121309 (4pp)