DFT insights into the electronic structure, mechanical behaviour, lattice dynamics and defect processes in the first Sc-based MAX phase Sc₂SnC

Here we employed the density functional theory calculations to investigate some physical properties of first Sc-based MAX phase Sc₂SnC including defect processes to compare with those of existing M₂SnC phases. The calculated structural properties are in good agreement with the experimental values. The new phase Sc₂SnC is structurally, mechanically and dynamically stable. Sc₂SnC is metallic with a mixture of covalent and ionic character. The covalency of Sc₂SnC including M₂SnC is mostly controlled by the effective valence. Sc₂SnC in M₂SnC family ranks second in the scale of deformability and softness. The elastic anisotropy level in Sc₂SnC is moderate compared to the other M₂SnC phases. The hardness and melting point of Sc₂SnC, including M₂SnC, follows the trend of bulk modulus. Like other members of the M₂SnC family, Sc₂SnC has the potential to be etched into 2D MXenes and has the potential to be a thermal barrier coating material.