Unprecedentedly large gap in HgBa$_2$Ca$_2$Cu$_3$O$_{8+δ}$ with the highest $T_c$ at ambient pressure
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arXiv
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| Autori principali: | , , , , , , , , |
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| Natura: | Preprint |
| Pubblicazione: |
2024
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| _version_ | 1866912234625564672 |
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| author | Wen, Chuanhao Hou, Zhiyong Akbari, Alireza Chen, Kailun Hong, Wenshan Yang, Huan Eremin, Ilya Li, Yuan Wen, Hai-Hu |
| author_facet | Wen, Chuanhao Hou, Zhiyong Akbari, Alireza Chen, Kailun Hong, Wenshan Yang, Huan Eremin, Ilya Li, Yuan Wen, Hai-Hu |
| contents | In cuprate superconductors, the highest $T_c$ is possessed by the HgBa$_2$Ca$_2$Cu$_3$O$_{8+δ}$ (Hg-1223) system at ambient pressure, but the reason remains elusive. Here we report the scanning tunneling measurements on the Hg-1223 single crystals with $T_c$ = 134 K. The observed gaps determined from the tunneling spectra (STS) can be categorized into two groups: the smaller gap $Δ_1$ ranges from about 45 to 70 meV, while the larger gap $Δ_2$ from about 65 to 98 meV. The STS was measured up to 200 K and the larger gap can persist well above $T_c$, indicating a pseudogap feature which may reflect the strong pairing energy in the inner layer. Interestingly, an extremely strong particle-hole asymmetry is observed in associating with a very robust coherence-like peak at the bias of the larger gap in the hole branch of the Bogoliubov dispersion. We argue that the observed asymmetry results may be from the interplay of a flat band (van Hove singularity) in the electronic spectrum and the large gap in the underdoped (inner) layer. A theoretical approach based on a trilayer model with an interlayer coupling can give a reasonable explanation. Our results provide deep insight into understanding the mechanism of superconductivity in cuprate superconductors. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2401_17079 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | Unprecedentedly large gap in HgBa$_2$Ca$_2$Cu$_3$O$_{8+δ}$ with the highest $T_c$ at ambient pressure Wen, Chuanhao Hou, Zhiyong Akbari, Alireza Chen, Kailun Hong, Wenshan Yang, Huan Eremin, Ilya Li, Yuan Wen, Hai-Hu Superconductivity Strongly Correlated Electrons In cuprate superconductors, the highest $T_c$ is possessed by the HgBa$_2$Ca$_2$Cu$_3$O$_{8+δ}$ (Hg-1223) system at ambient pressure, but the reason remains elusive. Here we report the scanning tunneling measurements on the Hg-1223 single crystals with $T_c$ = 134 K. The observed gaps determined from the tunneling spectra (STS) can be categorized into two groups: the smaller gap $Δ_1$ ranges from about 45 to 70 meV, while the larger gap $Δ_2$ from about 65 to 98 meV. The STS was measured up to 200 K and the larger gap can persist well above $T_c$, indicating a pseudogap feature which may reflect the strong pairing energy in the inner layer. Interestingly, an extremely strong particle-hole asymmetry is observed in associating with a very robust coherence-like peak at the bias of the larger gap in the hole branch of the Bogoliubov dispersion. We argue that the observed asymmetry results may be from the interplay of a flat band (van Hove singularity) in the electronic spectrum and the large gap in the underdoped (inner) layer. A theoretical approach based on a trilayer model with an interlayer coupling can give a reasonable explanation. Our results provide deep insight into understanding the mechanism of superconductivity in cuprate superconductors. |
| title | Unprecedentedly large gap in HgBa$_2$Ca$_2$Cu$_3$O$_{8+δ}$ with the highest $T_c$ at ambient pressure |
| topic | Superconductivity Strongly Correlated Electrons |
| url | https://arxiv.org/abs/2401.17079 |