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arXiv · 2501.10287

Beyond-Hubbard pairing in a cuprate ladder

Hari Padma·Jinu Thomas·Sophia TenHuisen·Wei He·Ziqiang Guan·Jiemin Li·Byungjune Lee·Yu Wang·Seng Huat Lee·Zhiqiang Mao·Hoyoung Jang·Valentina Bisogni·Jonathan Pelliciari·Mark P. M. Dean·Steven Johnston·Matteo Mitrano
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Abstract

The Hubbard model is believed to capture the essential physics of cuprate superconductors. However, recent theoretical studies suggest that it fails to reproduce a robust and homogeneous superconducting ground state. Here, using resonant inelastic x-ray scattering and density matrix renormalization group calculations, we show that magnetic excitations in the prototypical cuprate ladder Sr$_{14}$Cu$_{24}$O$_{41}$ are inconsistent with those of a simple Hubbard model. The magnetic response of hole carriers, contributing to an emergent branch of spin excitations, is strongly suppressed. This effect is the consequence of d-wave-like pairing, enhanced by nearly an order of magnitude through a large nearest-neighbor attractive interaction. The similarity between cuprate ladders and the two-dimensional compounds suggests that such an enhanced hole pairing may be a universal feature of superconducting cuprates.

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Hari Padma, Jinu Thomas, Sophia TenHuisen, Wei He, Ziqiang Guan, Jiemin Li, Byungjune Lee, Yu Wang, Seng Huat Lee, Zhiqiang Mao, Hoyoung Jang, Valentina Bisogni, Jonathan Pelliciari, Mark P. M. Dean, Steven Johnston, Matteo Mitrano. 2025-01-17. Beyond-Hubbard pairing in a cuprate ladder. https://doi.org/10.1103/physrevx.15.021049

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