Low-energy perspective of interacting electrons in the normal state of superconducting bilayer nickelate
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arXiv
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| Autores principales: | , , |
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| Formato: | Preprint |
| Publicado: |
2025
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| _version_ | 1866908366436040704 |
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| author | Lechermann, Frank Bötzel, Steffen Eremin, Ilya M. |
| author_facet | Lechermann, Frank Bötzel, Steffen Eremin, Ilya M. |
| contents | Developing a low-energy model is essential for understanding unconventional superconductivity in bilayer nickelate La$_3$Ni$_2$O$_7$. Here, we analyze distinct low-energy scenarios of the normal state by downfolding the ab-initio determined band structure and applying the mean-field regime of rotational-invariant slave-boson theory. We compare models based on the single-site two-orbital, the two-site four-orbital and a proposed minimal cluster (MC) picture. The latter builds up on three adapted orbitals located on the sites of the basic Ni-O-Ni cluster across the bilayer. Intriguing interplay between the Hund coupling $J_{\rm H}$ and the interlayer exchange $J_{\perp}$ is encountered in the multiorbital multi-site problem. While the tendency for interlayer Ni-$d_{z^2}$ singlet formation is pronounced, a complete localization remains hindered by the coupling to the Ni-$d_{x^2-y^2}$ orbitals. The correlation physics in the MC picture is peculiar with respect to the effective interorbital/site exchange. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2503_12412 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Low-energy perspective of interacting electrons in the normal state of superconducting bilayer nickelate Lechermann, Frank Bötzel, Steffen Eremin, Ilya M. Strongly Correlated Electrons Superconductivity Developing a low-energy model is essential for understanding unconventional superconductivity in bilayer nickelate La$_3$Ni$_2$O$_7$. Here, we analyze distinct low-energy scenarios of the normal state by downfolding the ab-initio determined band structure and applying the mean-field regime of rotational-invariant slave-boson theory. We compare models based on the single-site two-orbital, the two-site four-orbital and a proposed minimal cluster (MC) picture. The latter builds up on three adapted orbitals located on the sites of the basic Ni-O-Ni cluster across the bilayer. Intriguing interplay between the Hund coupling $J_{\rm H}$ and the interlayer exchange $J_{\perp}$ is encountered in the multiorbital multi-site problem. While the tendency for interlayer Ni-$d_{z^2}$ singlet formation is pronounced, a complete localization remains hindered by the coupling to the Ni-$d_{x^2-y^2}$ orbitals. The correlation physics in the MC picture is peculiar with respect to the effective interorbital/site exchange. |
| title | Low-energy perspective of interacting electrons in the normal state of superconducting bilayer nickelate |
| topic | Strongly Correlated Electrons Superconductivity |
| url | https://arxiv.org/abs/2503.12412 |