Theoretical Investigation of the Mechanical and Thermodynamic Properties of the Layered Yttrium Diborocarbides

Abstract

The mechanical, electronic, and thermodynamic properties of typical layered structure yttrium diborocarbides (YB2 C 2) were investigated by the density functional theory. The calculated lattice constants were slightly higher than the available experimental data. The elastic constants revealed that YB2 C 2 was mechanically stable. The bulk modulus (190.8 GPa), shear modulus (127.4 GPa), Young’s modulus (312.7 GPa), Poisson’s ratio (0.227), and Vickers hardness (18–19 GPa) were obtained, and the ductility, plasticity, and elastic anisotropy were further analyzed. The total and partial density of states were also calculated, indicating that the metallic character was mainly attributed to the contribution from Y-4d states and weakly hybridized with the 2p states from the B and C atoms. Finally, we obtained the Debye, melting, and the superconducting transition temperatures of YB2 C 2 as 824, 2239 and 2.38 K, respectively. Our study showed that YB2 C 2 offers potential in superconductivity or ultrahigh temperature applications.