Superconductivity from Quasiparticle Pairing of Intervalley Coherent State in Rhombohedral Trilayer Graphene
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arXiv
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| Format: | Preprint |
| Publié: |
2024
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| _version_ | 1866918485378990080 |
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| author | Chau, Chun Wang Chen, Shuai A. Law, K. T. |
| author_facet | Chau, Chun Wang Chen, Shuai A. Law, K. T. |
| contents | Superconductivity is observed in rhombohedral trilayer graphene in a narrow regime between the flavor-symmetric state and the symmetry breaking phase, which cannot be described by the conventional Bardeen-Cooper-Schrieffer theory. The measured coherence length, for instance, is roughly two orders of magnitude shorter than the value predicted by the Bardeen-Cooper-Schrieffer relation based on the large fermi velocity and an extremely low charge carrier density of the flavor-symmetric phase. To resolve the discrepancies, we propose that the rhombohedral trilayer graphene superconducting phase arises from the pairing of quasiparticles of the adjacent inter-valley coherent state. We illustrate the superconducting phenomenology using gapped Dirac cones with the chemical potential $μ$ close to the valence band's edge. Our findings indicate that the transition temperature $T_c$ obeys $T_c\propto ε_D\exp(-2/ρ_\mathrm{qp}U)$ with the density of states $ρ_\mathrm{qp}$ of intervalley coherent state quasiparticles, which is much suppressed compared to predictions from the Bardeen-Cooper-Schrieffer theory. The coherence length $ξ$ we predict behaves according to $ξ\sim v/\sqrt{μT_c}$ with $v$ being the velocity of Dirac cone. Applying our assumption to a microscopic model, our predictions align well with experimental data and effectively capture key measurable quantities such as the transition temperature $T_c$ and the coherence length $ξ$ without parameter fine-tuning. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2404_19237 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | Superconductivity from Quasiparticle Pairing of Intervalley Coherent State in Rhombohedral Trilayer Graphene Chau, Chun Wang Chen, Shuai A. Law, K. T. Superconductivity Mesoscale and Nanoscale Physics Strongly Correlated Electrons Superconductivity is observed in rhombohedral trilayer graphene in a narrow regime between the flavor-symmetric state and the symmetry breaking phase, which cannot be described by the conventional Bardeen-Cooper-Schrieffer theory. The measured coherence length, for instance, is roughly two orders of magnitude shorter than the value predicted by the Bardeen-Cooper-Schrieffer relation based on the large fermi velocity and an extremely low charge carrier density of the flavor-symmetric phase. To resolve the discrepancies, we propose that the rhombohedral trilayer graphene superconducting phase arises from the pairing of quasiparticles of the adjacent inter-valley coherent state. We illustrate the superconducting phenomenology using gapped Dirac cones with the chemical potential $μ$ close to the valence band's edge. Our findings indicate that the transition temperature $T_c$ obeys $T_c\propto ε_D\exp(-2/ρ_\mathrm{qp}U)$ with the density of states $ρ_\mathrm{qp}$ of intervalley coherent state quasiparticles, which is much suppressed compared to predictions from the Bardeen-Cooper-Schrieffer theory. The coherence length $ξ$ we predict behaves according to $ξ\sim v/\sqrt{μT_c}$ with $v$ being the velocity of Dirac cone. Applying our assumption to a microscopic model, our predictions align well with experimental data and effectively capture key measurable quantities such as the transition temperature $T_c$ and the coherence length $ξ$ without parameter fine-tuning. |
| title | Superconductivity from Quasiparticle Pairing of Intervalley Coherent State in Rhombohedral Trilayer Graphene |
| topic | Superconductivity Mesoscale and Nanoscale Physics Strongly Correlated Electrons |
| url | https://arxiv.org/abs/2404.19237 |