Anisotropic high-Tc superconductivity above 90 K in hole-doped boron-nitrogen clathrates at ambient pressure

Abstract

Breakthroughs in near-room-temperature superconductivity within clathrate hydrides underscore the effectiveness of theory-driven approaches to designing high-Tc superconductors. However, superconductivity in these clathrate hydrides has not been realized at low or ambient pressures. To explore phonon-mediated superconductors with Tc exceeding the liquid-nitrogen temperature under ambient pressure, this study investigates the crystal structure, metallization, electron-phonon coupling, and anisotropic superconducting behavior in hole-doped (BN)6 and (BN)5 clathrates, with configurations akin to CaH6 and LaH10, utilizing first-principles calculations in junction with Wannier interpolation technique. By solving the fully anisotropic Migdal-Eliashberg equations, this work reveals a positive correlation between Tc and hole-doping levels, with the highest Tc approximately 32 K and 96 K in hole-doped (BN)6 and (BN)5, respectively, and both with single anisotropic energy gap nature. The high-Tc superconductivity in B-N clathrates arises from two primary factors: the enhanced density of states at the Fermi level and the presence of strong B-N sp3-hybridized covalent σ-bonding bands. These insights provide a new perspective for revealing the superconductivity of B-N clathrates from an anisotropic perspective and offer valuable avenues for inducing high-Tc superconductors at ambient conditions.

Source-reported materials — not catalogue approval

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