First principles calculations on elasticity, electronic structure and bonding properties of antiperovskites ANTi3 (A = Al, In and Tl)

We use an ab initio pseudopotential plane wave (PP-PW) method within the generalized gradient approximation (GGA) and the local density approximation (LDA) to study the structural, elastic and electronic properties of the unexplored antiperovskite ANTi3 compounds. The elastic constants C11, C12, C44 and their pressure dependence are calculated. We derived the bulk, shear and Young's moduli for ideal monocrystalline and for polycrystalline ANTi3 aggregates which we have classified as ductile in nature. Band structures reveal that these compounds are conductors. The covalent ionic bands nature is due to the strong hybridization between Ti 3d and N 2p states. The Ti 3d states play dominant roles near the Fermi levels for all these compounds. The energy difference between spin polarized calculations and the nonspin polarized calculations indicate that ANTi3 compounds exhibit magnetism at their equilibrium lattice constants.

Research highlights
► In this study the B/G values of ANTi3 show that these materials behave as ductile.
► Band structures show that are conductors and exhibit magnetism.
► Therefore lead to lower Tc or no superconducting behavior in our compounds.
► The chemical bonding in ANTi3 compounds may be covalent–ionic.
► Elastic properties of our compounds show a correlation with the bonding properties.