Superconductivity Favored Anisotropic Phase Stiffness in Infinite-Layer Nickelates

Fuente: arXiv
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Auteurs principaux: Xu, Minyi, Qiu, Dong, Xu, Minghui, Guo, Yehao, Shen, Cheng, Yang, Chao, Sun, Wenjie, Nie, Yuefeng, Li, Zi-Xiang, Xiang, Tao, Qiao, Liang, Xiong, Jie, Li, Yanrong
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Publié: 2025
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author Xu, Minyi
Qiu, Dong
Xu, Minghui
Guo, Yehao
Shen, Cheng
Yang, Chao
Sun, Wenjie
Nie, Yuefeng
Li, Zi-Xiang
Xiang, Tao
Qiao, Liang
Xiong, Jie
Li, Yanrong
author_facet Xu, Minyi
Qiu, Dong
Xu, Minghui
Guo, Yehao
Shen, Cheng
Yang, Chao
Sun, Wenjie
Nie, Yuefeng
Li, Zi-Xiang
Xiang, Tao
Qiao, Liang
Xiong, Jie
Li, Yanrong
contents In unconventional superconductors such as cuprates and iron pnictides and chalcogenides, phase stiffness - a measure of the energy cost associated with superconducting phase variations - is on the same order of magnitude as the strength of Cooper pairing, translating to superconductivity governed by phase fluctuations. However, due to a lack of a direct experimental probe, there remains a fundamental gap in establishing microscopic picture between unconventional superconductivity and phase fluctuations. Here we show a vector current technique that allows for in-situ angle-resolved transport measurements, providing exclusive evidence suggesting an anisotropic nature of phase stiffness in infinite-layer nickelate superconductors. Pronounced anisotropy of in-plane resistance manifests itself in both normal and superconducting transition states, indicating crystal symmetry breaking. Remarkably, the electric conductivity of Nd0.8Sr0.2NiO2 peaks at 125° between the direction of the current and crystal principal axis, but this angle evolves to 160° near zero-resistance temperature. Further measurements reveal that the superconductivity is favored along a direction with minimized phase fluctuations, an orientation strikingly deviating from the symmetric direction imposed by both electronic anisotropy and the underlying crystal lattice. Identical measurements conducted on a prototypical cuprate superconductor yield consistent results, suggesting that this previously unknown behavior could be ubiquitous. By shielding insight into the contrasting anisotropy between electron fluid and superfluid, our findings provide clues for a unified framework for understanding unconventional superconductors
format Preprint
id arxiv_https___arxiv_org_abs_2502_14633
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Superconductivity Favored Anisotropic Phase Stiffness in Infinite-Layer Nickelates
Xu, Minyi
Qiu, Dong
Xu, Minghui
Guo, Yehao
Shen, Cheng
Yang, Chao
Sun, Wenjie
Nie, Yuefeng
Li, Zi-Xiang
Xiang, Tao
Qiao, Liang
Xiong, Jie
Li, Yanrong
Superconductivity
Strongly Correlated Electrons
In unconventional superconductors such as cuprates and iron pnictides and chalcogenides, phase stiffness - a measure of the energy cost associated with superconducting phase variations - is on the same order of magnitude as the strength of Cooper pairing, translating to superconductivity governed by phase fluctuations. However, due to a lack of a direct experimental probe, there remains a fundamental gap in establishing microscopic picture between unconventional superconductivity and phase fluctuations. Here we show a vector current technique that allows for in-situ angle-resolved transport measurements, providing exclusive evidence suggesting an anisotropic nature of phase stiffness in infinite-layer nickelate superconductors. Pronounced anisotropy of in-plane resistance manifests itself in both normal and superconducting transition states, indicating crystal symmetry breaking. Remarkably, the electric conductivity of Nd0.8Sr0.2NiO2 peaks at 125° between the direction of the current and crystal principal axis, but this angle evolves to 160° near zero-resistance temperature. Further measurements reveal that the superconductivity is favored along a direction with minimized phase fluctuations, an orientation strikingly deviating from the symmetric direction imposed by both electronic anisotropy and the underlying crystal lattice. Identical measurements conducted on a prototypical cuprate superconductor yield consistent results, suggesting that this previously unknown behavior could be ubiquitous. By shielding insight into the contrasting anisotropy between electron fluid and superfluid, our findings provide clues for a unified framework for understanding unconventional superconductors
title Superconductivity Favored Anisotropic Phase Stiffness in Infinite-Layer Nickelates
topic Superconductivity
Strongly Correlated Electrons
url https://arxiv.org/abs/2502.14633