Superconductivity in the kagome Hubbard model under the flat-band-preserving disorder
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arXiv
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| Formato: | Preprint |
| Publicado: |
2026
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| _version_ | 1866917182716248064 |
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| author | Kim, Jicheol Kim, Dong-Hee |
| author_facet | Kim, Jicheol Kim, Dong-Hee |
| contents | We investigate the disordered flat-band superconductivity within the attractive Hubbard model on the kagome lattice by contrasting the flat-band-preserving disorder [Phys. Rev. B 98, 235109 (2018)] with the random hopping disorder that breaks the flat-band degeneracy. Through Bogoliubov-de Gennes mean-field calculations, we find that the superfluid weight is much more robust under the flat-band-preserving disorder, while the system eventually undergoes a transition to an insulator as disorder becomes strong enough. The almost linear interaction-dependence of the superfluid weight in the weak coupling limit found with the flat-band-preserving disorder confirms the persistent flat-band signature, whereas the exponential behavior of a dispersive-band character arises with the random hopping counterpart. In addition, in the exact diagonalization of the one-particle density matrix, we identify an occupation spectrum structure attributed to the flat-band states, demonstrating the connection between the resilient flat band and the enhanced robustness of superconductivity. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2601_00540 |
| institution | arXiv |
| publishDate | 2026 |
| record_format | arxiv |
| spellingShingle | Superconductivity in the kagome Hubbard model under the flat-band-preserving disorder Kim, Jicheol Kim, Dong-Hee Superconductivity Strongly Correlated Electrons We investigate the disordered flat-band superconductivity within the attractive Hubbard model on the kagome lattice by contrasting the flat-band-preserving disorder [Phys. Rev. B 98, 235109 (2018)] with the random hopping disorder that breaks the flat-band degeneracy. Through Bogoliubov-de Gennes mean-field calculations, we find that the superfluid weight is much more robust under the flat-band-preserving disorder, while the system eventually undergoes a transition to an insulator as disorder becomes strong enough. The almost linear interaction-dependence of the superfluid weight in the weak coupling limit found with the flat-band-preserving disorder confirms the persistent flat-band signature, whereas the exponential behavior of a dispersive-band character arises with the random hopping counterpart. In addition, in the exact diagonalization of the one-particle density matrix, we identify an occupation spectrum structure attributed to the flat-band states, demonstrating the connection between the resilient flat band and the enhanced robustness of superconductivity. |
| title | Superconductivity in the kagome Hubbard model under the flat-band-preserving disorder |
| topic | Superconductivity Strongly Correlated Electrons |
| url | https://arxiv.org/abs/2601.00540 |