Pairing symmetry and superconductivity in La$_3$Ni$_2$O$_7$ thin films

Fuente: arXiv
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Main Authors: Qiu, Wenyuan, Luo, Zhihui, Hu, Xunwu, Yao, Dao-Xin
Format: Preprint
Published: 2025
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author Qiu, Wenyuan
Luo, Zhihui
Hu, Xunwu
Yao, Dao-Xin
author_facet Qiu, Wenyuan
Luo, Zhihui
Hu, Xunwu
Yao, Dao-Xin
contents The recent discovery of superconductivity with a transition temperature $T_c$ over 40 K in La$_3$Ni$_2$O$_7$ and (La,Pr)$_{3}$Ni$_2$O$_7$ thin films at ambient pressure marks an important step in the field of nickelate superconductors. Here, we perform a renormalized mean-field theory study of the superconductivity in $\mathrm{La_3Ni_2O_7}$ thin films, using a bilayer two-orbital $t-J$ model. Our result reveals an $s_\pm$-wave pairing symmetry driven by the strong interlayer superexchange coupling of $d_{z^2}$ orbital, resembling the pressurized bulk case. Also, we roughly reproduce the experimentally observed nodeless shape of the superconducting gap at the $β$ pocket and the superconducting $T_c$. In addition, by analysing the orbital-resolved pairing configurations and their projections onto Fermi surface, we find that the nodeless feature of $β$ pocket is related to the interlayer pairing within both $d_{z^2}$ and $d_{x^2-y^2}$ orbitals. Moreover, we identify a formation of the inplane inter-orbital $d$-wave pairing between $d_{z^2}$ and $d_{x^2-y^2}$ orbitals, which can even enhance the dominated interlayer $s_\pm$-wave.
format Preprint
id arxiv_https___arxiv_org_abs_2506_20727
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Pairing symmetry and superconductivity in La$_3$Ni$_2$O$_7$ thin films
Qiu, Wenyuan
Luo, Zhihui
Hu, Xunwu
Yao, Dao-Xin
Superconductivity
Strongly Correlated Electrons
The recent discovery of superconductivity with a transition temperature $T_c$ over 40 K in La$_3$Ni$_2$O$_7$ and (La,Pr)$_{3}$Ni$_2$O$_7$ thin films at ambient pressure marks an important step in the field of nickelate superconductors. Here, we perform a renormalized mean-field theory study of the superconductivity in $\mathrm{La_3Ni_2O_7}$ thin films, using a bilayer two-orbital $t-J$ model. Our result reveals an $s_\pm$-wave pairing symmetry driven by the strong interlayer superexchange coupling of $d_{z^2}$ orbital, resembling the pressurized bulk case. Also, we roughly reproduce the experimentally observed nodeless shape of the superconducting gap at the $β$ pocket and the superconducting $T_c$. In addition, by analysing the orbital-resolved pairing configurations and their projections onto Fermi surface, we find that the nodeless feature of $β$ pocket is related to the interlayer pairing within both $d_{z^2}$ and $d_{x^2-y^2}$ orbitals. Moreover, we identify a formation of the inplane inter-orbital $d$-wave pairing between $d_{z^2}$ and $d_{x^2-y^2}$ orbitals, which can even enhance the dominated interlayer $s_\pm$-wave.
title Pairing symmetry and superconductivity in La$_3$Ni$_2$O$_7$ thin films
topic Superconductivity
Strongly Correlated Electrons
url https://arxiv.org/abs/2506.20727