A statistical strained-tetrahedron model developed to better describe and understand the local structure of ternary zincblende crystals, interprets experimental EXAFS and far-infrared spectra. it considers five tetrahedron configurations distorted in shape and size, characteristic of ternary zincblende alloys, allows non random distributions, hence site occupation preferences, conserves coordination numbers, respects stoichiometry, and assumes next neighbor values determine preferences beyond next neighbor. Configuration probabilities have three degrees of freedom. The nineteen inter-ion crystal distances are constrained by tetrahedron structures; to avoid destructive stresses, we assume average tetrahedron volumes of both sublattices to relax to equal values. the number of distance free-parameters ≤7. Model estimates, compared to published EXAFS results, validate the model. knowing configuration probabilities, one writes the dielectric function for far-Infrared absorption or reflection spectra. Constraining assumptions restrict the number of degrees of freedom. unfolding experimental spectra yields SOP coefficient values and/or specific oscillator strengths. validation again confirms the model.
A. et al. (Tue,) studied this question.