Metallenes: Emergent superconductivity in atomically thin metal layers

Abstract

Atomically thin two-dimensional (2D) metals, termed metallenes, represent an ideal platform for exploring exotic superconducting states. However, their limited dynamical stability at atomic thickness makes the realization of superconductivity challenging. Through comprehensive high-throughput screening and first-principles calculations, we systematically investigate the energetics, dynamic and thermodynamic stability, and electronic and superconducting properties of elemental metallenes across 14 main-group elements in 8 different lattice configurations (i.e., hc, hex, sq, bhc, bhex, bsq, 1H, and 1T). Among the 112 metallenes screened, 31 are identified as dynamically stable, of which 19 exhibit superconductivity. Notably, the 1T−MoS2-like gallenene (1T-gallenene) exhibits the highest Tc of 6.90–9.79 K among all predicted 2D metallenes. Detailed analysis reveals that the strong electron-phonon coupling dynamically stabilizes out-of-plane phonon vibrations of Ga atoms, while simultaneously mediating surface Ga-p Cooper pairing and driving superconductivity. This mechanism is generalizable to other superconducting metallenes, as exemplified by isostructural configurations including Li, Na, Mg, Be, and Al. These results substantially expand the family of metallenes and pave a promising avenue for realizing exotic superconducting states in 2D elemental metals.

Source-reported materials — not catalogue approval

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