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arXiv · 2512.20689

Controlled pairing symmetries in a Fermi-Hubbard ladder with band flattening

J. P. Mendonça·S. Biswas·M. Dziurawiec·U. Bhattacharya·K. Jachymski·M. Aidelsburger·M. Lewenstein·M. M. Maśka·T. Grass
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Abstract

Band flattening has been identified as key ingredient to correlation phenomena in Moir\'e materials and beyond. Here, we examine strongly repulsive fermions on a ladder -- a minimal platform for unconventional $d$-wave pairing -- and show that flattening of the lower band through an additional diagonal hopping term produces non-Fermi liquid behavior, evidenced by the violation of Luttinger's theorem, as well as axial $d$-wave pairing correlations. Alternatively, plaquette ring exchange can also generate pairing, albeit with a distinct diagonal $d$-wave pairing symmetry. Hence, our finding showcases a competition of different unconventional pairing channels, and demonstrates via a simple model how band geometry can induce fermionic pairing. This offers broadly relevant insights for correlated flat-band systems, ranging from ultracold atoms to strongly interacting electrons in solids.

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J. P. Mendonça, S. Biswas, M. Dziurawiec, U. Bhattacharya, K. Jachymski, M. Aidelsburger, M. Lewenstein, M. M. Maśka, T. Grass. 2025-12-22. Controlled pairing symmetries in a Fermi-Hubbard ladder with band flattening. https://arxiv.org/abs/2512.20689

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