Enhanced superconductivity in two-dimensional : First-principles investigation of electron-phonon coupling and topological properties
Phys. Rev. B 112, 224504 – Published 2 December, 2025
DOI: https://doi.org/10.1103/t7nc-p31n
Abstract
Two-dimensional materials with intrinsic superconductivity and nontrivial topology represent a frontier for discovering exotic quantum states and potential applications in quantum devices. Here, we report the first comprehensive theoretical investigation of superconductivity in monolayer and bilayer . The monolayer has been recently synthesized experimentally and features a unique checkerboard lattice with topological nodal lines. Following this experimental breakthrough, we predict phonon-mediated superconductivity with transition temperatures () of 3.8 K (monolayer) and 7.9 K (bilayer) arising from strong electron-phonon coupling ( and 0.84, respectively) mediated primarily by Cu -orbitals and low-frequency phonon modes. The bilayer shows 84% enhancement through additional interlayer vibrational modes that strengthen Cu -orbital coupling via enhanced out-of-plane vibrations. Strain engineering enhances monolayer to 4.5 K under 0.2% compressive strain through optimized electronic density of states and phonon softening. We identify a practical synthesis pathway involving multilayer growth followed by controlled exfoliation with moderate energy cost (). Our results demonstrate that , featuring coexisting topological nodal lines and phonon-mediated superconductivity, represents a promising experimental platform for investigating potential topological superconducting behavior in accessible two-dimensional systems.