Strain-modulated superconductivity of monolayer Tc₂B₂

Two-dimensional (2D) superconductors have attracted significant research interest due to their promising potential applications in optoelectronic and microelectronic devices. Herein, we employ first-principles calculations to predicted a new 2D conventional superconductor, Tc₂B₂, demonstrating its stable structural configuration. Remarkably, under biaxial strain, the superconducting transition temperature (T_c) of Tc₂B₂ demonstrates a significant enhancement, achieving 19.5 K under 3% compressive strain and 9.2 K under 11% tensile strain. Our study reveals that strain-induced modifications in Fermi surface topology significantly enhance the Fermi surface nesting effect, which amplifies electron–phonon coupling interactions and consequently elevates T_c. Additionally, the presence of the Lifshitz transition results in a more pronounced rise in T_c under compressive strain compared to tensile strain. These insights offer important theoretical guidance for designing 2D superconductors with high-T_c through strain modulation.