X-ray and neutron scattering study of Si-rich Si-Ge single crystals - art.no. 035204

The local atomic environments of homogeneous Si-rich Si-Ge single crystals were studied using x-ray and neutron diffuse scattering. No evidence of eit her chemical short-range order or clustering was observed. Static atomic di splacements, however, were clearly present and are consistent with an expan sion of the lattice in the vicinity of the Ge atoms. The dispersion of the acoustic phonons was also measured using inelastic neutron scattering. The acoustic modes of the Si-Ge alloy were found to lie nearer those of pure Si than expected from the homologous relationship found between pure Si and p ure Ge.