LOCALIZED VIBRATIONAL-MODES OF HYDROGEN-IMPURITY COMPLEXES IN GAAS

The results of ab initio calculations performed on the complexes formed between hydrogen and donor and acceptor atoms in gallium arsenide are reported. The equilibrium geometries and electronic properties are presented. A parameter free determination of the vibrational properties of the entire defect complex has been performed allowing a more complete comparison with infrared absorption experiments to be made. Local structural distortions far larger than previously expected are proposed explaining the absence of certain absorption lines.