Structural, elastic and electronic properties of ACTi3 (A=Al, In and Tl) antiperovskite

First principle calculations were performed to investigate the structural, elastic and electronic properties of unexplored antiperovskite ACTi3, with A=Al, In and Tl. The calculated structural parameters were found to be in good agreement with the available experimental data, with deviations being less than 2.7%. The bulk modulus was found to be equal to 155 GPa for AlCTi3 and to a value 5% lower, 147 GPa, for TlCTi3. For values of applied pressures up to 40 GPa, elastic moduli were calculated and the mechanical stability criteria were verified. The band structure of these compounds has been found to display a metallic character, with strong ionic-covalent bonds between Ti and C atoms, and ionic bonds along A and Ti atoms. The overlap population analysis showed that the stiffness decreases with an increase in the antibonding state between Ti and A atoms.