Structural, mechanical, and electronic properties of Ta2B by First-principle calculations

The structure, phase stability, and elastic properties of Ta2B have been carefully investigated by density functional theory. We propose a new orthorhombic Cmcm structure that is more stable than the previous I4/mcm. Combined with a study of the relationship between enthalpy pressure and convex hull, the Cmcm structure is found to be stable at atmospheric pressure and, at zero pressure, the stable phases are Ta2B, TaB, Ta3B4, Ta5B6, and TaB2, in agreement with experimental results. Above a pressure of 60 GPa, Ta2B becomes unstable.