Rational design of high-temperature superconductors from hydrides to boron clathrates

Near-room-temperature superconductivity has been achieved in hydrogen-rich materials under ultrahigh hydrostatic pressures, yet such extreme conditions remain a fundamental barrier to practical application. The search for ambient-pressure high-temperature superconductors has therefore increasingly turned to boron–carbon (B–C) and boron–nitrogen (B–N) clathrate systems, in which hydrogen is replaced by the light elements B, C, and N to form rigid covalent cage frameworks that retain the high phonon frequencies essential for elevated superconducting critical temperatures (Tc). Here, we present a systematic statistical analysis of reported B–C and B–N superconducting compounds and reveal the critical role of the interplay between the electron–phonon coupling constant λ and the logarithmic average phonon frequency ω log in determining Tc. Our statistical analysis reveals that the variation of Tc in B–C and B–N systems cannot be described by either λ or ω log alone but instead arises from their combined effects and intrinsic interplay. Extending the mass-ratio screening framework of binary hydrides to ternary B–C and B–N superconductors, we further identify two design descriptors for high Tc, namely, a low valence electron count and a small guest–host mass ratio MX/(MTotal−MX). These design rules provide a quantitative framework for the rational design and high-throughput discovery of ambient-pressure high-temperature superconductors.