Nematicity in iron pnictides: phase competition and emergent symmetry

Fuente: arXiv
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Autores principales: Wang, Yiming, Liu, Changle, Wu, Shan, Wu, Jianda, Si, Qimiao, Yu, Rong
Formato: Preprint
Publicado: 2025
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author Wang, Yiming
Liu, Changle
Wu, Shan
Wu, Jianda
Si, Qimiao
Yu, Rong
author_facet Wang, Yiming
Liu, Changle
Wu, Shan
Wu, Jianda
Si, Qimiao
Yu, Rong
contents The phase diagram of iron-based superconductors contains a host of electronic orders, which are intimately connected with their superconductivity. Here we analyze the fluctuations of one type of nematic order in another. Our analysis leads to an emergent U(1) symmetry at a first-order transition between a nematic phase and a $C_4$-symmetric charge-ordered phase. We characterize the continuous symmetry in terms of a certain hidden Lie algebra that links the different orders. This emergent symmetry leads to a Goldstone mode at the transition and causes softening of excitations in the nematic and charge sectors near the transition. The underlying physics bears a resemblance to the anisotropic XZ spin model, with the nematic order and charge $C_4$ order parameters playing the roles of the $x$ and $z$ components of the magnetization vector, respectively. We provide the experimental evidence in support of the proposed effects, and discuss the general implications of our results for the physics of iron-based superconductors and other correlated systems.
format Preprint
id arxiv_https___arxiv_org_abs_2505_24847
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Nematicity in iron pnictides: phase competition and emergent symmetry
Wang, Yiming
Liu, Changle
Wu, Shan
Wu, Jianda
Si, Qimiao
Yu, Rong
Strongly Correlated Electrons
Superconductivity
The phase diagram of iron-based superconductors contains a host of electronic orders, which are intimately connected with their superconductivity. Here we analyze the fluctuations of one type of nematic order in another. Our analysis leads to an emergent U(1) symmetry at a first-order transition between a nematic phase and a $C_4$-symmetric charge-ordered phase. We characterize the continuous symmetry in terms of a certain hidden Lie algebra that links the different orders. This emergent symmetry leads to a Goldstone mode at the transition and causes softening of excitations in the nematic and charge sectors near the transition. The underlying physics bears a resemblance to the anisotropic XZ spin model, with the nematic order and charge $C_4$ order parameters playing the roles of the $x$ and $z$ components of the magnetization vector, respectively. We provide the experimental evidence in support of the proposed effects, and discuss the general implications of our results for the physics of iron-based superconductors and other correlated systems.
title Nematicity in iron pnictides: phase competition and emergent symmetry
topic Strongly Correlated Electrons
Superconductivity
url https://arxiv.org/abs/2505.24847