Year: 1967
Type: article
Abstract: A two-neighbour Born-von Kármán model is applied to the diamond crystal. The nearest neighbours are assumed to interact with general forces and central, angular and torsional forces are considered in the second-neighbour interactions. One of the five force constants that occur in this model is taken as a free parameter and is fitted to the experimental frequencies at the zone boundaries in the (100) and (111) directions. A good qualitative fit, substantially better than the corresponding fit in the case of germanium and silicon, is obtained. The phonon spectrum is calculated using the Fourier series expansion method. The specific heat of diamond is evaluated in the temperature range 0-300 °k and is found to agree quite well with the experimental results. Finally, the analysis of the dependence of the frequency and amplitude of the localized mode due to an isotopic impurity on its mass is made.
Author: K G Aggarwal
Institution: Indian Institute of Technology Kanpur
Language: English
Subfield: Materials Chemistry
Field: Materials Science
Domain: Physical Sciences
Open Access status: bronze
OpenAlex ID: W2015436658