First-principles study of the structural, elastic and electronic properties of the anti-perovskites SnBSc3 and PbBSc3

For the first time, the structural, elastic and electronic properties of the scandium-based boride anti-perovskites SnBSc3 and PbBSc3 have been investigated using a first-principles pseudo-potential plane-wave method within the generalized gradient approximation and the local density approximation. The equilibrium lattice constants, bulk moduli and their pressure derivatives, elastic constants, elastic wave velocities, electronic band structures, densities of states and bonding nature are calculated for the single-crystals SnBSc3 and PbBSc3. Pressure dependence of the elastic properties is studied up to 50 GPa. From the anisotropic elastic constants, we have estimated the isotropic elastic parameters and related properties, namely the shear modulus, Young's modulus, Poisson's ratio, Lamé’s constants, sound velocities and Debye temperature, for the polycrystalline SnBSc3 and PbBSc3 aggregates.