Feshbach resonance in a strongly repulsive ladder of mixed dimensionality: A possible scenario for bilayer nickelate superconductors

Lange, Hannah and Homeier, Lukas and Demler, Eugene and Schollwoeck, Ulrich and Grusdt, Fabian and Bohrdt, Annabelle (2024) Feshbach resonance in a strongly repulsive ladder of mixed dimensionality: A possible scenario for bilayer nickelate superconductors. PHYSICAL REVIEW B, 109 (4): 045127. ISSN 2469-9950, 2469-9969

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Abstract

Since the discovery of superconductivity in cuprate materials, the minimal ingredients for high-Tc superconductivity have been an outstanding puzzle. Motivated by the recently discovered nickelate bilayer superconductor La3Ni2O7 under pressure, we study a minimal bilayer model, in which, as in La3Ni2O7, interlayer and intralayer magnetic interactions but no interlayer hopping are present: A mixed-dimensional (mixD) t-J model. In the setting of a mixD ladder, we show that the system exhibits a crossover associated with a Feshbach resonance: From a closed-channel-dominated regime of tightly bound bosonic pairs of holes to an open-channel-dominated regime of spatially more extended Cooper pairs. The crossover can be tuned by varying doping, or by a nearest-neighbor Coulomb repulsion V that we include in our model. Using density matrix renormalization group simulations and analytical descriptions of both regimes, we find that the ground state is a Luther-Emery liquid, competing with a density wave of tetraparton plaquettes at commensurate filling delta = 0.5 at large repulsion, and exhibits a pairing dome where binding is facilitated by doping. Our observations can be understood in terms of pairs of correlated spinon-chargon excitations constituting the open channel, which are subject to attractive interactions mediated by the closed channel of tightly bound chargon-chargon pairs. When the closed channel is lowered in energy by doping or tuning V, a Feshbach resonance is realized, associated with a dome in the binding energy. Our predictions can be directly tested in state-of-the art quantum simulators, and we argue that the pairing mechanism we describe may be realized in the nickelate bilayer superconductor La3Ni2O7.

Item Type: Article
Uncontrolled Keywords: CONDENSATION; PHYSICS
Subjects: 500 Science > 530 Physics
Divisions: Physics > Institute of Theroretical Physics > Chair Professor Grifoni > Group Milena Grifoni
Depositing User: Dr. Gernot Deinzer
Date Deposited: 09 Dec 2025 09:58
Last Modified: 09 Dec 2025 09:58
URI: https://pred.uni-regensburg.de/id/eprint/65309

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