Electronic and Mechanical Properties of Tetragonal Nb₂Al Under High Pressure: First-Principles Calculations

We have investigated the structure, density of states, mechanical stability, elastic properties, and Debye temperature of tetragonal Nb₂Al under high pressure using the generalized gradient approximation WC (GGA-WC) functional within density functional theory (DFT). Our obtained lattice constants were in good agreement with the reported experimental and theoretical data at zero pressure. The volume decreased with the increasing pressure. The effects of pressure on the electronic properties have been discussed. The elastic constants under pressure have been calculated, which all satisfied the stability criterion, meaning that tetragonal Nb₂Al was mechanical stability from 0 to 100 GPa. Then, the mechanical properties including bulk modulus B, shear modulus G, Young’s modulus E, G/B, and Poisson’s ratio ν under pressure were determined using the Voigt-Reuss-Hill method. The G/B value suggested that tetragonal Nb₂Al exhibited ductile behavior under pressure. Poisson’s ratio indicated that the interatomic forces in tetragonal Nb₂Al were mainly central forces. Finally, the transverse, longitudinal, and average sound velocities and Debye temperature of tetragonal Nb₂Al under pressure have been estimated.