First-Principles Investigations on the Elastic Properties of Platinum Group Metals (Pt, Pd, and Ru)

Abstract

The structural, mechanical, and thermodynamic properties of platinum group metals (Pt, Pd, and Ru) were systematically investigated by first-principles calculations based on density functional theory. Comparative studies show that Ru has the best comprehensive mechanical properties. Based on the Pugh’s rule and Poisson’s ratio, it is judged that Pt and Pd are ductility materials, and Ru exhibits obvious brittleness. Furthermore, the elastic anisotropy is also discussed by plotting both the 3D contours and the 2D planar projections of Young's modulus and shear modulus. The predicted elastic anisotropy factors indicate that the degree of elastic anisotropy of Pd is significant, while Ru has the smallest elastic anisotropy. By using the Clarke’s model, the minimum thermal conductivities of these metals have also been analyzed, and the results indicate that the low minimum thermal conductivity is proportional to the Debye temperature ΘD. The above results can provide a valuable reference for revealing the microscopic deformation mechanism and designing new materials.