Theoretical investigation of the superconducting pairing symmetry in a bilayer two-orbital model of pressurized La$_3$Ni$_2$O$_7$

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1. Verfasser: Gao, Yi
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Veröffentlicht: 2024
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author Gao, Yi
author_facet Gao, Yi
contents We investigate the superconducting pairing symmetry in pressurized La$_3$Ni$_2$O$_7$ based on a bilayer two-orbital model. There are two symmetric bands $α$ and $γ$, as well as two antisymmetric ones $β$ and $δ$. It is found that the $γ$ band induces considerable ferromagnetic spin fluctuation and prefers an odd-frequency, $s$-wave spin triplet pairing state. The addition of the other bands gradually suppresses the ferromagnetic spin fluctuation and enhances the antiferromagnetic ones. The superconducting pairing then evolves from a spin triplet into a $d$-wave spin singlet, and finally into an $s_\pm$-wave one. The competition between the $d$-wave and $s_\pm$-wave pairings relies on whether the ferromagnetic spin fluctuation is suppressed completely or not.
format Preprint
id arxiv_https___arxiv_org_abs_2412_11429
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Theoretical investigation of the superconducting pairing symmetry in a bilayer two-orbital model of pressurized La$_3$Ni$_2$O$_7$
Gao, Yi
Superconductivity
We investigate the superconducting pairing symmetry in pressurized La$_3$Ni$_2$O$_7$ based on a bilayer two-orbital model. There are two symmetric bands $α$ and $γ$, as well as two antisymmetric ones $β$ and $δ$. It is found that the $γ$ band induces considerable ferromagnetic spin fluctuation and prefers an odd-frequency, $s$-wave spin triplet pairing state. The addition of the other bands gradually suppresses the ferromagnetic spin fluctuation and enhances the antiferromagnetic ones. The superconducting pairing then evolves from a spin triplet into a $d$-wave spin singlet, and finally into an $s_\pm$-wave one. The competition between the $d$-wave and $s_\pm$-wave pairings relies on whether the ferromagnetic spin fluctuation is suppressed completely or not.
title Theoretical investigation of the superconducting pairing symmetry in a bilayer two-orbital model of pressurized La$_3$Ni$_2$O$_7$
topic Superconductivity
url https://arxiv.org/abs/2412.11429