Origin of superconductivity in non-BCS superconductors

Determine the microscopic origin of superconductivity in non-BCS superconductors, including cuprate materials, where the underlying pairing mechanism remains unidentified.

Background

The paper notes that despite decades of research since the early proposals of high-temperature superconductivity without fundamental limits, the highest critical temperature achieved at ambient pressure remains that of the cuprates, and theoretical understanding has lagged. In particular, for non-BCS superconductors such as the cuprates, the fundamental mechanism responsible for superconductivity has not been conclusively established.

The authors frame their dielectric-environment engineering (resonant anti-shielding) approach as mechanism-agnostic, which can, in principle, enhance Cooper pairing irrespective of the specific pairing origin. This underscores the broader unresolved problem of identifying the pairing mechanism in non-BCS families, which remains a central obstacle to reliable predictive calculations of critical temperatures.

References

Equally disappointing has been theoretical progress, with the origin of superconductivity in non-BCS superconductors (including cuprate and possibly other families) remaining unknown or, at best, unclear.

— Enhancing superconductivity via engineered polaronic environment  (2408.03288 - Kempa et al., 2024) in Page 1, opening paragraph

At present, the data at hand does not allow us to unambiguously distinguish between these possibilities.

— Superconductivity at the metal-insulator phase boundary in a bulk nickelate at ambient pressure  (2609.19686 - Ahn et al., 17 Sep 2026) in Conclusion

Namely, the microscopic mechanism behind repulsively mediated pairing of electrons, the cornerstone of all high-$T_c$ superconductivity (and unconventional superconductivity more broadly), has not been accessible in this way so far, and remains unresolved.

— Predicting critical temperature in quantum simulators for high-$T_c$ superconductivity: the matrix product state plus mean field approach  (2608.18861 - Köhler et al., 19 Aug 2026) in Section 1, Introduction