Intra-unit-cell Josephson scanning tunneling spectroscopy of the cuprate Bi1.2Pb0.8Sr2CaCu2O8+δ
Abstract
The predominantly dx2−y2-wave pairing symmetry of cuprate superconductors is well established, yet its microscopic manifestation in local Cooper-pair tunneling remains less explored. Here, we investigate Bi1.2Pb0.8Sr2CaCu2O8+δ, using Josephson scanning tunneling spectroscopy with a conventional s-wave superconducting Pb tip. We observe a zero-bias conductance enhancement whose approximately quadratic dependence on junction conductance is consistent with phase-diffusive Josephson tunneling. Atomic-resolution conductance maps and site-resolved spectra reveal a pronounced intra-unit-cell modulation, with enhanced Josephson response near oxygen sites and strong suppression near copper sites and along diagonal directions. Microscopic calculations incorporating the bilayer electronic structure and realistic Wannier-based tunneling matrix elements reproduce the observed spatial pattern through interference between pairing contributions of opposite signs. Our results reveal how the sign-changing d-wave superconducting order parameter manifests itself in atomic-scale Josephson tunneling, providing complementary evidence for unconventional pairing symmetry in cuprates.
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BibTeX
@misc{yao2026intraunitcell,
title = {{Intra-unit-cell Josephson scanning tunneling spectroscopy of the cuprate Bi$_1.2$Pb$_0.8$Sr$_2$CaCu$_2$O$_8+δ$}},
author = {Fengyu Yao and Jiong Mei and Wenjin Mao and Runxin Li and Yuchen Huo and Miaomiao Wang and Quanxing Wei and Guihao Jia and Qing Qu and Cui Ding and Lin Zhao and Zhuoyu Chen and Ming-Qiang Ren and Kun Jiang and X. J. Zhou and Jin-Feng Jia and Qi-Kun Xue and Yu-Jie Sun},
howpublished = {arXiv},
year = {2026},
month = nov,
doi = {10.48550/arxiv.2611.04815},
eprint = {2611.04815},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2611.04815},
}
RIS
TY - UNPB
TI - Intra-unit-cell Josephson scanning tunneling spectroscopy of the cuprate Bi_1.2Pb_0.8Sr_2CaCu_2O_8+δ
AU - Fengyu Yao
AU - Jiong Mei
AU - Wenjin Mao
AU - Runxin Li
AU - Yuchen Huo
AU - Miaomiao Wang
AU - Quanxing Wei
AU - Guihao Jia
AU - Qing Qu
AU - Cui Ding
AU - Lin Zhao
AU - Zhuoyu Chen
AU - Ming-Qiang Ren
AU - Kun Jiang
AU - X. J. Zhou
AU - Jin-Feng Jia
AU - Qi-Kun Xue
AU - Yu-Jie Sun
PY - 2026
DA - 2026/11/03
PB - arXiv
DO - 10.48550/arxiv.2611.04815
UR - https://arxiv.org/abs/2611.04815
AB - The predominantly d_x^2−y^2-wave pairing symmetry of cuprate superconductors is well established, yet its microscopic manifestation in local Cooper-pair tunneling remains less explored. Here, we investigate Bi_1.2Pb_0.8Sr_2CaCu_2O_8+δ, using Josephson scanning tunneling spectroscopy with a conventional s-wave superconducting Pb tip. We observe a zero-bias conductance enhancement whose approximately quadratic dependence on junction conductance is consistent with phase-diffusive Josephson tunneling. Atomic-resolution conductance maps and site-resolved spectra reveal a pronounced intra-unit-cell modulation, with enhanced Josephson response near oxygen sites and strong suppression near copper sites and along diagonal directions. Microscopic calculations incorporating the bilayer electronic structure and realistic Wannier-based tunneling matrix elements reproduce the observed spatial pattern through interference between pairing contributions of opposite signs. Our results reveal how the sign-changing d-wave superconducting order parameter manifests itself in atomic-scale Josephson tunneling, providing complementary evidence for unconventional pairing symmetry in cuprates.
ER -