Conventional High-Temperature Superconductivity at Ambient Pressure in Zincblende-Like Light-Element Compounds

To validate the feasibility of high-temperature superconductivity in light-element compounds at ambient pressure, we designed a class of <i>XY</i>₄<i>Z</i>₄ (<i>Y</i>₄<i>Z</i>₄ = B₄N₄, Si₄C₄, B₄P₄) structures based on the zincblende configuration. Using high-throughput calculations based on density functional theory, we evaluate 201 compounds and identify 17 materials that are both dynamically and mechanically stable at ambient pressure. These materials demonstrate an insulator-to-metal transition achieved through carrier doping, including 12 superconductors, with 4 of them showing a <i>T</i>_c above 20 K. Notably, LiB₄N₄ and MgB₄P₄ stand out with predicted <i>T</i>_c values of 67 and 45 K, respectively, both surpassing the <i>T</i>_c of MgB₂. A high electronic density of states at the Fermi level, combined with phonon softening in the low-frequency region, enhances electron-phonon coupling strength. The exploration of strong-bond and lightweight materials will pave the way for achieving high-temperature superconductivity at ambient pressure.