Phonon scattering by substitutional impurity in cubic lattices
Bal Krishna Agrawal · Journal of Physics C Solid State Physics · 1970
The resonance denominator of the phonon scattering T-matrix has been analysed according to the irreducible representations of the point group pertaining to the perturbation caused by a substitutional impurity in the scalar model of Montroll and Potts (1955). The vector nature of the atomic displacement has been considered in determining the point group and its various irreducible representations. It is shown that the earlier results obtained on the assumption of the scalar nature of the atomic displacement are retained if one applies certain unitary transformations to some of the symmetry coordinates obtained in the vector model considered in the present paper.