Superconductivity in nickelate and cuprate superconductors with strong bilayer coupling
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arXiv
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| Auteurs principaux: | , , , , , , |
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| Format: | Preprint |
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2023
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| _version_ | 1866916337917362176 |
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| author | Fan, Zhen Zhang, Jian-Feng Zhan, Bo Lv, Dingshun Jiang, Xing-Yu Normand, Bruce Xiang, Tao |
| author_facet | Fan, Zhen Zhang, Jian-Feng Zhan, Bo Lv, Dingshun Jiang, Xing-Yu Normand, Bruce Xiang, Tao |
| contents | The discovery of superconductivity at 80 K under high pressure in La$_3$Ni$_2$O$_7$ presents the groundbreaking confirmation that high-$T_c$ superconductivity is a property of strongly correlated materials beyond cuprates. We use density functional theory (DFT) calculations of the band structure of La$_3$Ni$_2$O$_7$ under pressure to verify that the low-energy bands are composed almost exclusively of Ni 3$d_{x^2-y^2}$ and O 2$p$ orbitals. We deduce that the Ni 3$d_{z^2}$ orbitals are essentially decoupled by the geometry of the high-pressure structure and by the effect of the Ni Hund coupling being strongly suppressed, which results from the enhanced interlayer antiferromagnetic interaction between $d_{z^2}$ orbitals and the strong intralayer hybridization of the $d_{x^2-y^2}$ orbitals with O 2$p$. By introducing a tight-binding model for the Fermi surfaces and low-energy dispersions, we arrive at a bilayer $t$-$t_\perp$-$J$ model with strong interlayer hopping, which we show is a framework unifying La$_3$Ni$_2$O$_7$ with cuprate materials possessing similar band structures, particularly the compounds La$_2$CaCu$_2$O$_6$, Pb$_2$Sr$_2$YCu$_3$O$_8$, and EuSr$_2$Cu$_2$NbO$_8$. We use a renormalized mean-field theory to show that these systems should have ($d$+$is$)-wave superconductivity, with a dominant $d$-wave component and the high $T_c$ driven by the near-optimally doped $β$ band, while the $α$ band adds an $s$-wave component that should lead to clear experimental signatures. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2312_17064 |
| institution | arXiv |
| publishDate | 2023 |
| record_format | arxiv |
| spellingShingle | Superconductivity in nickelate and cuprate superconductors with strong bilayer coupling Fan, Zhen Zhang, Jian-Feng Zhan, Bo Lv, Dingshun Jiang, Xing-Yu Normand, Bruce Xiang, Tao Superconductivity The discovery of superconductivity at 80 K under high pressure in La$_3$Ni$_2$O$_7$ presents the groundbreaking confirmation that high-$T_c$ superconductivity is a property of strongly correlated materials beyond cuprates. We use density functional theory (DFT) calculations of the band structure of La$_3$Ni$_2$O$_7$ under pressure to verify that the low-energy bands are composed almost exclusively of Ni 3$d_{x^2-y^2}$ and O 2$p$ orbitals. We deduce that the Ni 3$d_{z^2}$ orbitals are essentially decoupled by the geometry of the high-pressure structure and by the effect of the Ni Hund coupling being strongly suppressed, which results from the enhanced interlayer antiferromagnetic interaction between $d_{z^2}$ orbitals and the strong intralayer hybridization of the $d_{x^2-y^2}$ orbitals with O 2$p$. By introducing a tight-binding model for the Fermi surfaces and low-energy dispersions, we arrive at a bilayer $t$-$t_\perp$-$J$ model with strong interlayer hopping, which we show is a framework unifying La$_3$Ni$_2$O$_7$ with cuprate materials possessing similar band structures, particularly the compounds La$_2$CaCu$_2$O$_6$, Pb$_2$Sr$_2$YCu$_3$O$_8$, and EuSr$_2$Cu$_2$NbO$_8$. We use a renormalized mean-field theory to show that these systems should have ($d$+$is$)-wave superconductivity, with a dominant $d$-wave component and the high $T_c$ driven by the near-optimally doped $β$ band, while the $α$ band adds an $s$-wave component that should lead to clear experimental signatures. |
| title | Superconductivity in nickelate and cuprate superconductors with strong bilayer coupling |
| topic | Superconductivity |
| url | https://arxiv.org/abs/2312.17064 |