Anisotropic mechanical behavior and thermal attributes of antiferromagnetic UX2(X=P, As, Sb) materials: A density functional and elasticity theories study

Abstract

In this work, we delve into the investigation of mechanical and thermal properties of antiferromagnetic UX2 (X=P, As, Sb), which are structured in the unique anti-Cu2Sb-type tetragonal form. The study’s principal findings revolve around the revelation of distinctive compressibility patterns and an observed preference for shear deformation in these compounds. These patterns are notably marked by a lower compressibility along the [100] direction than the [001] one, and the ease of shear deformation on the (100) plane compared to the (001) one. Intriguingly, our findings identify these compounds as residing on the brink of the brittle/ductile borderline as per Pugh’s ratio and Poisson’s ratio. Furthermore, the mechanical strength in these materials is significantly influenced by shear deformation, a fact indicated by the values of bulk and Young’s modulus. Among the UX2 (X=P, As, Sb) compounds, our analysis of the Debye temperature singles out UP2 as an outstanding performer due to its higher Debye temperature. A noteworthy aspect of this study is the quicker propagation of longitudinal waves over transverse waves, as indicated by the wave velocity and anisotropy calculations. We bring forth an enriched understanding of the anisotropic behavior of these materials in terms of bulk modulus, Young’s modulus, shear modulus, and Poisson’s ratio. The predicted high melting temperatures of the UX2 (X=P, As, Sb) compounds, coupled with the computed heat capacities aligning well with existing experimental data, point towards their potential applicability in high-temperature settings. Collectively, our study not only validates the methodologies employed but also brings to light fascinating new insights into the mechanical and thermal properties of these compounds, deepening our understanding of the intricate interplay between their atomic constitution and physical properties.