Fonones en cristales con estructura de diamante

Abstract

A study of the vibrational modes of crystals with diamond structure is presented. In the study we apply the Keating's model for describing the short-range interatomic interactions and incorporating, in the simplest way, three-body interactions, associated with the deformation of the angle between two covalent bonds. Within the framework of the harmonic approximation, we obtain analytical expressions for the dispersion relations of phonons with wave vectors along three high-symmetry directions: $[001]$, $[110]$ and $[111]$. These expressions show clearly the effect of the force constants upon the phonon band structure for crystals with diamond structure. Our results are illustrated in the specific case of C.