First-principles study on electronic structure and elastic properties of hexagonal Zr2Sc

An investigation into the equation of state (EOS), electronic and elastic properties of Zr2SC has been conducted by first-principles pseudopotential calculations. The calculated EOS is well consistent with the recent experimental reports. The absence of band gap at the Fermi level and the finite value of the density of states at the Fermi energy reveal the metallic behavior of Zr2SC. From the variations of elastic constants with pressure, we find that hexagonal Zr2SC is most stable in the pressure range from 0 to 100 GPa, which is consistent with the experimental observations. The strong hybridization of Zr 4d states, S 3p states and C 2p states and the presence of pseudogap stabilize the structure of Zr2SC. By analyzing the ratio between the bulk and shear moduli, we conclude that Zr2SC is brittle in nature. The mechanism of brittleness of Zr2SC originated from the large value of Zr atom occupying the internal parameter z.