LOCAL STRUCTURES IN ZINCBLENDE-TYPE RANDOM SOLID-SOLUTIONS

The local structures of zincblende-type solid solutions A1-xBxC can be described with five distorted unit cells based on a phenomenological valence force-field approach. Bond lengths and strain energies in thes e solid solutions can be obtained. The distorted feature of the local structure is well described by the five distorted unit cells. This str uctural model has been applied to 18 A1-xBxC systems. Results are comp ared with those from extended x-ray absorption fine structure and demo nstrate that all the first- and second-neighbour bond lengths are in a greement with experimental values, with the largest divergence being a bout 0.01 angstrom. In addition, this model is also compared with the five special tetrahedra model.