First-Principles Investigations of Electronic Structures, Mechanical Properties, and Thermodynamic Characteristics of Scandium Carbide Compounds

Abstract

Aiming to study the electronic structures, mechanical properties, and thermodynamic characteristics within framework of density function theory for scandium carbide (Sc_xC_y) compounds, first-principles calculations were performed. The calculated cohesive energy and formation enthalpy indicate that the compounds have the thermodynamically stable structures. Their electronic characteristics indicate that ScC, Sc₂C, Sc₂C₃, and Sc₃C₄ present metallic character but Sc₄C₃ presents semiconductor character. According to the stress-strain method, the elastic constants were calculated. In a framework of the Voigte-Reusse-Hill approximation, bulk modulus (B), shear modulus (G), Young’s modulus (E), Poisson’s ratio (σ), and Vickers hardness (${{H}_{{v}}}$) were analyzed. The largest value of B, G, E are found from Sc₂C₃. Both ScC and Sc₂C₃ are ductile whereas other compounds are brittle. Mechanical anisotropy analysis indicates that Sc₂C₃ has the highest anisotropy because its percent anisotropy A_G (0.038) is the largest one. Furthermore, the relationship of thermodynamic properties such as specific heat capacity, entropy, Helmholtz free energy and internal energy with temperature were analyzed.