Sharma Model Research Articles

Temperature Dependence of Electrical and Thermal Resistivities of Noble Metals

Abstract The electrical and thermal resistivities of noble metals copper, silver and gold have been de­termined at different temperatures in the free electron approximation using Sharma and Joshi's model for the phonon dispersion relations. A modified Houston's method is used to evaluate the formidable integral over the scattering vector. The normal and Umklapp contributions to the resistivity are considered separately from the conservation laws of wave vector. The theoretical and experimental resistivity curves are found to be of similar nature, but the agreement is not detailed. The Lorentz numbers of noble metals deduced from theoretical and experimental resistivity data show considerable deviation from Wiedemann-Franz law.

Crystal dynamics of light weight alkali metals

The lattice dynamics of lithium, sodium and potassium have been studied on a modified de Launay type angular force interaction, where an account is also taken of the presence of conduction electrons, on the lines of the Sharma and Joshi model. A calculation of the phonon dispersion relations, the Debye temperature and the Debye-Waller factor gives very good agreement with the experimental results.