Theory of superconductivity and mass enhancement near CDW critical point based on Bethe-Salpeter equation method: application to cuprates
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arXiv
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| Formato: | Preprint |
| Publicado: |
2025
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| _version_ | 1866908505542230016 |
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| author | Yamakawa, Youichi Kontani, Hiroshi |
| author_facet | Yamakawa, Youichi Kontani, Hiroshi |
| contents | In recent years, charge-channel orders in strongly correlated metals have attracted great attention. Famous examples are the electronic nematic orders in cuprates and iron-based superconductors, and Star-of-David order in kagome metals. Critical phenomena and unconventional superconductivity arising from fluctuations of such charge-channel orders are central issues today; however, the essential role is played by the vertex corrections, which are the many-body effects that are dropped in conventional mean-field type approximations. To solve this difficulty, in this study, we propose the Bethe-Salpeter equation theory to evaluate electron-electron interactions in two dimensional Hubbard models. This method satisfies the criteria of the Baym-Kadanoff conserving approximation. Here, we find that an attractive interaction in the charge channel emerges from the Aslamazov-Larkin vertex corrections that describe the interference processes among spin fluctuations. Applying this method to the square-lattice Hubbard model, we reveal that the cooperation of attractive charge fluctuations and repulsive spin fluctuations yields high-$T_c$ $d$-wave superconductivity together with enhanced effective mass. These results naturally explain the phase diagram of cuprate superconductors, where strong-coupling $d$-wave superconductivity appears near the charge-order quantum critical point. The theory can also be applied to multi-orbital Hubbard models, like iron-based and nickelate superconductors, suggesting broad potential for future applications. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2508_19536 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Theory of superconductivity and mass enhancement near CDW critical point based on Bethe-Salpeter equation method: application to cuprates Yamakawa, Youichi Kontani, Hiroshi Superconductivity Strongly Correlated Electrons In recent years, charge-channel orders in strongly correlated metals have attracted great attention. Famous examples are the electronic nematic orders in cuprates and iron-based superconductors, and Star-of-David order in kagome metals. Critical phenomena and unconventional superconductivity arising from fluctuations of such charge-channel orders are central issues today; however, the essential role is played by the vertex corrections, which are the many-body effects that are dropped in conventional mean-field type approximations. To solve this difficulty, in this study, we propose the Bethe-Salpeter equation theory to evaluate electron-electron interactions in two dimensional Hubbard models. This method satisfies the criteria of the Baym-Kadanoff conserving approximation. Here, we find that an attractive interaction in the charge channel emerges from the Aslamazov-Larkin vertex corrections that describe the interference processes among spin fluctuations. Applying this method to the square-lattice Hubbard model, we reveal that the cooperation of attractive charge fluctuations and repulsive spin fluctuations yields high-$T_c$ $d$-wave superconductivity together with enhanced effective mass. These results naturally explain the phase diagram of cuprate superconductors, where strong-coupling $d$-wave superconductivity appears near the charge-order quantum critical point. The theory can also be applied to multi-orbital Hubbard models, like iron-based and nickelate superconductors, suggesting broad potential for future applications. |
| title | Theory of superconductivity and mass enhancement near CDW critical point based on Bethe-Salpeter equation method: application to cuprates |
| topic | Superconductivity Strongly Correlated Electrons |
| url | https://arxiv.org/abs/2508.19536 |