High-throughput design of 211−M2AX compounds

Based on high-throughput density-functional theory calculations, we investigated the stability and physical properties of the MAX phases with the chemical formula ${\mathrm{M}}_{2}\mathrm{AX}$. Starting from 1080 possible compositions with the M element being one of the $3d$, $4d$, or $5d$ transition metal elements, the A element being a main group element, and X being either C or N, we identified 82 compounds satisfying all three stability criteria (thermodynamic, mechanical, and dynamic stabilities), in addition to 48 synthesized systems as a validation of our workflow. The trend in the stability was analyzed based on the crystal orbital Hamilton population, concluding that increasing the number of electrons on the A and M sites destabilizes the MAX phase. The mechanical, thermoelectric, and topological properties of the candidate compounds are characterized by detailed calculations, resulting in anisotropic thermoelectric effect for all MAX compounds and a promising candidate topological insulator.