Model calculation of optically active lattice vibrations of an A1-xBxC alloy (for example, Hg1-cCdxTe)

A dynamic model of the crystal lattice of an «ideal» substitutional A 1−x B x C alloy with the zincblende structure is considered in the rigid-ion approximation with a short-range interaction between the nearest neighbors and a long-range Coulomb interaction. The replacement of an A ion with a B ion is regarded as only a change in the mass of the atom. The effect of the boundaries and of a uniform volume distribution of the A and B ions is reduced by investigating a large (∼ 3000 atoms) fragment of the crystal lattice. The frequencies of the optical vibrations in the alloy are calculated for different values of two parameters: the force constant k of the central interaction between the nearest neighbors and the ionic charge ± Q