Pressure effects on structure, mechanical properties and thermal conductivity of V2SnC: a first-principles study

Abstract

ABSTRACT Recently, a new layered-ternary compound V2SnC was successfully synthesised by reacting V, Sn, and C powder mixture at 1000°C. Its space group was identified as P63 /mmc. In this work, the structural, mechanical properties, and thermal conductivity of this new layered-ternary compound have been studied under pressure up to 100 GPa by density functional theory. The calculated lattice parameters and cell volume of V2SnC at the ground state are in good coincidence with the experimental values. With the increase of pressure, the a-axis of V2SnC crystal structure has greater compressibility than the c-axis. In addition, the calculated results of elastic constants and phonon dispersion curves indicated that V2SnC is mechanically and dynamically stable from 0 to 100 GPa. Furthermore, the influence of pressure on bulk modulus B, shear modulus G, aggregate acoustic velocities vm , Debye temperature ΘD , Poisson’s ratio σ, and Grüneisen parameter γ are systematically investigated. Meanwhile, the elastic anisotropy of V2SnC under external pressure is also studied for the first time. Finally, the minimum thermal conductivity of V2SnC under external pressure is further studied. The results show that this material has good thermal insulation performance.