Atomic-scale imaging of electronic nematicity in ferropnictides

Fuente: arXiv
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Main Authors: Cheng, Qiang-Jun, Wang, Yong-Wei, Ren, Ming-Qiang, Deng, Ze-Xian, Lou, Cong-Cong, Ma, Xu-Cun, Xue, Qi-Kun, Song, Can-Li
Format: Preprint
Published: 2025
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author Cheng, Qiang-Jun
Wang, Yong-Wei
Ren, Ming-Qiang
Deng, Ze-Xian
Lou, Cong-Cong
Ma, Xu-Cun
Xue, Qi-Kun
Song, Can-Li
author_facet Cheng, Qiang-Jun
Wang, Yong-Wei
Ren, Ming-Qiang
Deng, Ze-Xian
Lou, Cong-Cong
Ma, Xu-Cun
Xue, Qi-Kun
Song, Can-Li
contents Electronic nematicity, a correlated state characterized by broken rotational symmetry, has been recognized as a ubiquitous feature intertwined with unconventional electron pairing in various iron-based superconductors. Here we employ spectroscopic-imaging scanning tunneling microscopy to visualize atomic-scale electronic nematicity directly on FeAs planes of a prototypical ferropnictide BaFe$_2$As$_2$. Spatially, the nematic order appears as 4$a_{\textrm{Fe}}$-spaced stripes ($a_{\textrm{Fe}} \sim $ 0.28 nm is the in-plane Fe-Fe distance) within homogeneously and orthogonally oriented nano-domains. The energy-resolved conductance maps reveal a pronounced energy-dependence of the nematic order parameter that experiences a sign change at approximately 30 meV. This characteristic behavior coincides with energy-dependent orbital splitting previously identified in momentum space, but is remarkably visualized in real space for the first time in our study. Moreover, the electronic nematicity exhibits pronounced sensitivity to single impurities and is notably suppressed by cobalt substitution for Fe atoms, promoting optimal superconductivity when nematic fluctuations are strongest. Our results provide pivotal experimental insights for developing a microscopic model of nematic order, thus paving the way to study its complex relationship with unconventional superconductivity.
format Preprint
id arxiv_https___arxiv_org_abs_2506_16282
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Atomic-scale imaging of electronic nematicity in ferropnictides
Cheng, Qiang-Jun
Wang, Yong-Wei
Ren, Ming-Qiang
Deng, Ze-Xian
Lou, Cong-Cong
Ma, Xu-Cun
Xue, Qi-Kun
Song, Can-Li
Superconductivity
Electronic nematicity, a correlated state characterized by broken rotational symmetry, has been recognized as a ubiquitous feature intertwined with unconventional electron pairing in various iron-based superconductors. Here we employ spectroscopic-imaging scanning tunneling microscopy to visualize atomic-scale electronic nematicity directly on FeAs planes of a prototypical ferropnictide BaFe$_2$As$_2$. Spatially, the nematic order appears as 4$a_{\textrm{Fe}}$-spaced stripes ($a_{\textrm{Fe}} \sim $ 0.28 nm is the in-plane Fe-Fe distance) within homogeneously and orthogonally oriented nano-domains. The energy-resolved conductance maps reveal a pronounced energy-dependence of the nematic order parameter that experiences a sign change at approximately 30 meV. This characteristic behavior coincides with energy-dependent orbital splitting previously identified in momentum space, but is remarkably visualized in real space for the first time in our study. Moreover, the electronic nematicity exhibits pronounced sensitivity to single impurities and is notably suppressed by cobalt substitution for Fe atoms, promoting optimal superconductivity when nematic fluctuations are strongest. Our results provide pivotal experimental insights for developing a microscopic model of nematic order, thus paving the way to study its complex relationship with unconventional superconductivity.
title Atomic-scale imaging of electronic nematicity in ferropnictides
topic Superconductivity
url https://arxiv.org/abs/2506.16282