Bond–electromagnetic origin of superconducting pairing across materials

We develop a bond–electromagnetic framework in which superconducting pairing originates from dynamic covalent bonds whose fluctuations generate a real–space pairing kernel. Bond–centered singlets emerge from these structural fluctuations, while long–range superconductivity appears when they become electromagnetically frozen into a phase–coherent network, as quantified by the London kernel and the superfluid stiffness. Within this framework, the microscopic pairing scale $$T_{\textrm{pair}}$$ is determined directly from experimentally accessible structural quantities—including bond geometry, hybridization symmetry, dielectric screening, and the logarithmic bond–frequency moment—through a structural reformulation of the Allen–Dynes expression. The conversion of $$T_{\textrm{pair}}$$ into the observed superconducting transition temperature $$T_c$$ is then governed by the electromagnetic rigidity of the material. Using only structural inputs, the framework reproduces pairing scales across representative materials and coupling regimes. For elemental Al, $$T_{\textrm{pair}}$$ is obtained in a structurally parameter–free manner, while for Pb it is constrained solely by independently established ranges of the coupling strength. To probe structure–driven pairing in systems with reduced phase stiffness, we analyze FeSe under hydrostatic pressure. A structurally constrained form $$T_{\textrm{pair}}(P)=T_0\exp (a_1 P - a_2 P^2)$$ naturally captures the pressure–induced rise, maximum, and curvature of the superconducting dome, with the resulting trajectory spanning the experimentally observed transition region from the resistive onset to the zero–resistance state without invoking pressure–dependent spectroscopic input. These results establish a structure–anchored origin of superconducting pairing across distinct materials classes and demonstrate that experimentally accessible bond dynamics provide a practical materials–level criterion for linking lattice structure, electromagnetic response, and superconducting coherence.