Durandurdu, Murat2025-09-252025-09-2520250002-78201551-2916https://doi.org/10.1111/jace.20493https://hdl.handle.net/20.500.12573/4472The high-pressure behavior of an amorphous boron carbon nitride (BC4N) 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 sp3 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 BC4N 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 sp2-to-sp3 transition, suggesting that such a transformation could occur around 29 GPa under experimental conditions.eninfo:eu-repo/semantics/closedAccessAb InitioAmorphousBoron CarbonitrideGraphite-LikeArticle10.1111/jace.204932-s2.0-105003965745