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| Format: | Preprint |
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2025
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| Online Access: | https://arxiv.org/abs/2501.05254 |
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| _version_ | 1866908669947412480 |
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| author | Xu, Han-Xiang Guterding, Daniel |
| author_facet | Xu, Han-Xiang Guterding, Daniel |
| contents | The recent discovery of superconductivity in the bilayer Ruddlesden-Popper nickelate La$_3$Ni$_2$O$_7$ under high pressure has generated much interest in the superconducting pairing mechanism of nickelates. Despite extensive work, the superconducting pairing symmetry in La$_3$Ni$_2$O$_7$ remains unresolved, with conflicting results even for identical methods. We argue that different superconducting states in La$_3$Ni$_2$O$_7$ are in close competition and highly sensitive to the choice of interaction parameters as well as pressure-induced changes in the electronic structure. Our study uses a multi-orbital Hubbard model, incorporating all Ni $3d$ and O $2p$ states. We analyze the superconducting pairing mechanism of La$_3$Ni$_2$O$_7$ within the random phase approximation and find a transition between $d$-wave and sign-changing $s$-wave pairing states as a function of pressure and interaction parameters, which is driven by spin fluctuations with different wave vectors. These spin fluctuations with incommensurate wave vectors cooperatively stabilize a superconducting order parameter with $d_{x^2-y^2}$ symmetry for realistic model parameters. Simultaneously, their competition may be responsible for the absence of magnetic order in La$_3$Ni$_2$O$_7$, demonstrating that magnetic frustration and superconducting pairing can arise from the same set of incommensurate spin fluctuations. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2501_05254 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Incommensurate spin fluctuations and competing pairing symmetries in La$_3$Ni$_2$O$_7$ Xu, Han-Xiang Guterding, Daniel Superconductivity Strongly Correlated Electrons The recent discovery of superconductivity in the bilayer Ruddlesden-Popper nickelate La$_3$Ni$_2$O$_7$ under high pressure has generated much interest in the superconducting pairing mechanism of nickelates. Despite extensive work, the superconducting pairing symmetry in La$_3$Ni$_2$O$_7$ remains unresolved, with conflicting results even for identical methods. We argue that different superconducting states in La$_3$Ni$_2$O$_7$ are in close competition and highly sensitive to the choice of interaction parameters as well as pressure-induced changes in the electronic structure. Our study uses a multi-orbital Hubbard model, incorporating all Ni $3d$ and O $2p$ states. We analyze the superconducting pairing mechanism of La$_3$Ni$_2$O$_7$ within the random phase approximation and find a transition between $d$-wave and sign-changing $s$-wave pairing states as a function of pressure and interaction parameters, which is driven by spin fluctuations with different wave vectors. These spin fluctuations with incommensurate wave vectors cooperatively stabilize a superconducting order parameter with $d_{x^2-y^2}$ symmetry for realistic model parameters. Simultaneously, their competition may be responsible for the absence of magnetic order in La$_3$Ni$_2$O$_7$, demonstrating that magnetic frustration and superconducting pairing can arise from the same set of incommensurate spin fluctuations. |
| title | Incommensurate spin fluctuations and competing pairing symmetries in La$_3$Ni$_2$O$_7$ |
| topic | Superconductivity Strongly Correlated Electrons |
| url | https://arxiv.org/abs/2501.05254 |