SKM 2023 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 63: Superconductivity: Theory
TT 63.5: Talk
Friday, March 31, 2023, 10:30–10:45, HSZ 103
Superconductivity from repulsive interactions due to strong-coupling to a Mott-insulating layer — •Clara S. Weber1,2, Dante M. Kennes1, and Martin Claassen2 — 1RWTH Aachen, Aachen, Germany — 2University of Pennsylvania, Philadelphia, USA
While superconductors in their conventional form are established by effective attractive interactions, mechanisms for emergent electronic pairing from strong repulsive electron-electron interactions remain under considerable debate. Here, we establish a strong-coupling mechanism that realizes intertwined superconductivity and magnetic order in a Kondo-like bilayer system with purely repulsive interactions, composed of a two-dimensional Mott insulator with strong Hubbard interactions coupled to a layer of weakly-interacting itinerant electrons. Remarkably, this model allows for a rigorous strong-coupling analysis, where we find that itinerant electrons in the nearly-metallic layer are subject to an effective attractive electron-electron interaction as a function of magnetic ordering in the Mott-insulating layer. We carefully study this behavior numerically using large scale DMRG calculations and find that the superconducting behavior persists in a wide parameter range beyond the strong-coupling regime. Additionally, we classify the rich magnetic phase diagram and find a 2-site antiferromagnetic and a 4-site antiferromagnetic phase, along with a phase separation regime. Finally, we discuss possible applications and realizations of the proposed mechanism.