Phonon Spectra and Thermal Properties of Some fcc Metals Using the Embedded-Atom Method

TL;DR

This study uses embedded-atom potentials to calculate phonon spectra and thermal properties of six fcc metals, comparing results with experimental data and highlighting areas of good agreement and discrepancies.

Contribution

It provides detailed phonon and thermodynamic property calculations for six fcc metals using the embedded-atom method, with comprehensive comparison to experimental data.

Findings

Good agreement for lattice constants and bulk moduli

Underestimation of Grüneisen parameter and Debye temperature by about 10%

Reasonable match of phonon frequencies for Ag and Cu with experiments

Abstract

By employing the analytic embedded-atom potentials of Mei {\it et al.} [Phys. Rev. B 43, 4653 (1991)] we have calculated the phonon dispersion spectra for six fcc metals: Cu, Ag, Au, Ni, Pd and Pt. We have also investigated thermal properties of these metals within the quasiharmonic approximation. Results for the lattice constants, coefficients of linear thermal expansion, isothermal and adiabatic bulk moduli, heat capacities at constant volume and constant pressure, Debye temperatures and Gr\"uneisen parameters as a function of temperature are presented. The computed results are compared with the available experimental data. The comparison shows a generally good agreement between the calculated and experimental values for all thermodynamic properties studied. Isothermal and adiabatic bulk moduli and the specific heats are reproduced reasonably well, while the Gr\"uneisen parameter and Debye temperature are underestimated by about 10%. The calculated phonon frequencies for Ag and Cu agree well with the results from inelastic neutron scattering experiments. However, there is considerable room for improvement in the phonon frequencies for Ni, Pd, Pt and Au, particularly at high phonon wave vectors close to the Brillouin zone boundary. The coefficient of linear thermal expansion is underestimated in most cases except for Pt and Au. The results are good for Pt up to 1000K and for Au up to 500 K.