Superconductivity enhancement in topological nodal-line beryllium diboride

Abstract High-temperature conventional superconductivity at ambient conditions beyond MgB 2 presents key challenges in the dynamic stabilization of compositional structures. However, the isostructural beryllium diboride (BeB 2 ) phase lacks ambient-pressure dynamics stability, thus prohibiting superconductivity. Here, we predict a novel superconducting BeB 2 phase with P 6 3 c m symmetry featuring distorted hexagonal boron layers. The Wurtzitic gauche boron framework favors thermodynamic stability at ambient pressure by modulating anharmonic beryllium displacements. Interestingly, mirror symmetry is observed to protect topological nodal lines in electronic states. Eliashberg function computations estimate strong electron–phonon coupling strength for the BeB 2 phase beyond MgB 2 . High superconducting transition temperature achieves enhancement by mediating with broadened phonon modes attributed to atomic displacements. Our work can inspire wide interest in designing and modulating high-temperature superconducting structures with topology, especially offering potential exploration within meta-stable crystallographic databases.