Pressure‐induced quenchable superhard tetrahedral amorphous phase of BC 4 N

Abstract The high‐pressure behavior of an amorphous boron carbon nitride (BC 4 N) composition is investigated using constant‐pressure ab initio molecular dynamics simulations. A first‐order phase transformation into a tetrahedral amorphous phase with a high fraction of sp 3 bonding is observed. This tetrahedral phase is quenchable and exhibits ultra‐high incompressibility and a high Vickers hardness (46 GPa), placing it firmly in the category of superhard materials, comparable to tetrahedral amorphous carbon. Tetrahedral amorphous BC 4 N demonstrates semiconducting behavior with a narrow bandgap of 0.4 eV, making it suitable for applications requiring both mechanical robustness and moderate electronic conductivity. Thermodynamic analyses confirm the likelihood of a first‐order sp 2 ‐to‐sp 3 transition, suggesting that such a transformation could occur around 29 GPa under experimental conditions.