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arXiv · 2609.09730

Record-Breaking Elemental Superconductivity in Tetralayer Kagome Borophene

Yingnan Liu·Yan Liu·Renyu Duan·Menghui Wang·Meiling Xu·Hanyu Liu·Shoutao Zhang
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Abstract

Superconductivity above the liquid-nitrogen temperature remains rare in two-dimensional elemental crystals, where strong covalent bonding often yields high phonon frequencies but insufficient electron-phonon coupling. Here, using first-principles calculations and fully anisotropic Migdal-Eliashberg theory, we predict tetralayer kagome borophene (TKB) stabilized by ABAB covalent stacking, as a liquid-nitrogen-temperature elemental superconductor. With a predicted critical temperature of 102 K, TKB sets a record-high value among previously reported elemental superconductors. Unlike known high-Tc boron-based superconductors dominated by in-plane sigma-bonding states and high-frequency in-plane B-B stretching modes, TKB realizes an out-of-plane s-pz-bonding-mediated pairing mechanism, in which interlayer s-pz bonding states at the Fermi level are strongly coupled to low-frequency out-of-plane vibrations of boron atoms. These results reveal a distinct out-of-plane pairing channel in multilayer borophene and establish covalent stacking engineering as a potential route for high-Tc superconductivity in two-dimensional materials.

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Yingnan Liu, Yan Liu, Renyu Duan, Menghui Wang, Meiling Xu, Hanyu Liu, Shoutao Zhang. 2026-09-09. Record-Breaking Elemental Superconductivity in Tetralayer Kagome Borophene. https://arxiv.org/abs/2609.09730

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