DFT insights into the electronic structure, mechanical behaviour, lattice dynamics and defect processes in the first Sc-based MAX phase Sc(2)SnC

Here we employed the density functional theory calculations to investigate some physical properties of first Sc-based MAX phase Sc(2)SnC including defect processes to compare with those of existing M(2)SnC phases. The calculated structural properties are in good agreement with the experimental values. The new phase Sc(2)SnC is structurally, mechanically and dynamically stable. Sc(2)SnC is metallic with a mixture of covalent and ionic character. The covalency of Sc(2)SnC including M(2)SnC is mostly controlled by the effective valence. Sc(2)SnC in M(2)SnC family ranks second in the scale of deformability and softness. The elastic anisotropy level in Sc(2)SnC is moderate compared to the other M(2)SnC phases. The hardness and melting point of Sc(2)SnC, including M(2)SnC, follows the trend of bulk modulus. Like other members of the M(2)SnC family, Sc(2)SnC has the potential to be etched into 2D MXenes and has the potential to be a thermal barrier coating material.