Systematic ab initio studies were made of the electronic and structural properties of the disordered phase of the Si1-xGex alloy. For the defect free alloy, it was found that the Si¯Si bond length has a tendency to maintain its natural value (x = 0) all the way up to x > 0.5, similarly to what was found experimentally. The vacancy was also analyzed and it was noted, as expected for a structurally as well as chemically disordered solid, that there was no local symmetry around the vacancy site. Finally, some studies of the alloy were performed under pressures of to 30GPa, and it was found that the structure was highly distorted in some cases, indicating that an amorphous phase may be found in the pressure region of the diamond to β-Sn phase transition.

Ab Initio Studies of the Si1-xGex Alloy and its Intrinsic Defects. P.Venezuela, A.J.R.da Silva, C.da Silva, G.M.Dalpain, A.Fazzio: Computational Materials Science, 2001, 22[1-2], 62-6