Impurity vibrations of copper defect complexes in gallium arsenide crystals

Dynamical properties of several copper defect complexes in GaAs are studied. The complexes studied include models for the C and F centers recently investigated experimentally by Gross, Safarov, Sedov, and Marushchak. It is shown that these models are capable of giving rise to resonance modes whose frequencies agree with the positions of peaks in the optical spectra of these defect complexes, when reasonable changes in the force constants coupling the substitutional copper impurities to the host crystal are included in the dynamical models. In addition the vibronic and infrared absorption spectra of these complexes have been calculated.