Prediction of high-temperature ambient-pressure superconductivity in hexagonal boron-rich clathrates

Inspired by recent predictions of superconductivity in B-C framework clathrates, we employ density functional theory to explore potential superconductors among hexagonal hydride-substituted compounds with compositions XB${}_8$C, XB${}_7$C${}_2$, XB${}_6$C${}_3$, XB${}_3$C${}_6$, XB${}_2$C${}_7$, and XBC${}_8$. Our high-throughput calculations on 96 compounds reveal several dynamically stable candidates exhibiting superconductivity at ambient pressure. Analysis of electronic structures and electron-phonon coupling demonstrates that CaB${}_8$C, SrB${}_8$C, and BaB${}_8$C possess superconducting transition temperatures ($T_c$) exceeding 50 K, with CaB${}_8$C exhibiting the highest predicted $T_c$ of 77.1 K among all stable compounds studied. These findings expand the family of B-C clathrate superconductors and provide valuable insights for experimental efforts aimed at discovering novel superconducting materials.