Evidence of the stability of Mo2TiAlC2 from first principles calculations and its thermodynamical and optical properties

The elastic, thermodynamic, and optical properties of Mo2TiAlC2 are investigated by first-principles calculations. Our results indicate that the a axis is stiffer than c axis within 0-100 GPa. Elastic constants calculations predict the large stability range of Mo2TiAlC2 under pressure. Several important thermodynamic properties are discussed detailedly, including the Debye temperature, thermal expansion coefficient, and heat capacity. The bonding properties are studied from the elastic quantities and electronic properties. The electronic properties are investigated, including the energy band structure, and density of states. The evidence of the instability of Mo3AlC2 and stability of Mo2TiAlC2 are successfully obtained.