<i>Ab initio</i>study of the elastic anomalies in Pd-Ag alloys

Abstract

Ab initio total-energy calculations, based on the exact muffin-tin orbital method, are used to determine the elastic properties of ${\text{Pd}}_{1\ensuremath{-}x}{\text{Ag}}_{x}$ random alloys in the face-centered-cubic crystallographic phase. The compositional disorder is treated within the coherent-potential approximation. The single crystal and polycrystalline elastic constants and the Debye temperature are calculated for the whole range of concentration, $0\ensuremath{\le}x\ensuremath{\le}1$. It is shown that the variation in the elastic parameters of Pd-Ag alloys with chemical composition strongly deviates from a simple linear or parabolic trend. The complex electronic origin of these anomalies is demonstrated.