Enhanced superconductivity in two-dimensional Cu2N: First-principles investigation of electron-phonon coupling and topological properties

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 Cu2N. The monolayer Cu2N 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 (Tc) of 3.8 K (monolayer) and 7.9 K (bilayer) arising from strong electron-phonon coupling (λ=0.76 and 0.84, respectively) mediated primarily by Cu d-orbitals and low-frequency phonon modes. The bilayer shows 84% Tc enhancement through additional interlayer vibrational modes that strengthen Cu d-orbital coupling via enhanced out-of-plane vibrations. Strain engineering enhances monolayer Tc 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 (0.97J/m2). Our results demonstrate that Cu2N, 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.

Source-reported materials — not catalogue approval

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