Superpotential enhanced superconductivity and robust stiffness shaped by quantum geometry

Artikel i vetenskaplig tidskrift, 2026

Enhancing superconductivity through material design is a central goal in quantum materials research. Moiré engineering, where twisting stacked layers creates long-wavelength modulations and flat bands, amplifies electronic correlations and raises the superconducting critical temperature Tc, but is largely confined to van der Waals materials with limited tunability. Here we explore an alternative: imposing artificial superpotentials on homogeneous systems to engineer flat minibands. We show that a periodic superpotential in a two-dimensional system enhances superconductivity by reconstructing electronic bands and creating regions of large density of states, substantially increasing Tc. Unlike conventional flat-band systems, where superfluid stiffness arises solely from quantum geometry, a modulated system also inherits kinetic energy from filled minibands below the Fermi level, coexisting with a positive quantum geometric contribution to yield finite, robust stiffness. The resulting state remains resilient against weak to moderate disorder. These findings establish superlattice engineering as a tunable route to enhanced superconductivity beyond twist-based moiré systems, and a promising platform for next-generation superconductors.