Direct real-space imaging of sign-reversal superconducting state by scanning Josephson tunneling
Abstract
Phase-sensitive experiments based on Josephson tunneling have been considered as a pivotal method to determine the pairing symmetry in high-temperature (high-Tc) cuprate superconductors. However, in iron-based superconductors, traditional phase-sensitive experiments face setbacks because of the complexity of pairing symmetry in multiband systems. Here, using scanning Josephson tunneling microscopy (SJTM), we report the half-unit-cell periodic Josephson tunneling modulations in monolayer high-Tc Fe(Te,Se) film epitaxially grown on SrTiO3(001). The Josephson tunneling almost vanishes along the lines connecting next-nearest-neighbor Fe atoms under an s-wave superconducting tip. Combined with single-particle tunneling spectra showing the full superconducting gap, our experimental results are consistent with the sign-reversal nodeless d-wave pairing symmetry. Our findings provide sub-unit-cell scale superconducting phase information for understanding the mechanism of high-Tc superconductivity. We anticipate our work as a starting point for atomically resolved Josephson interference experiments using SJTM in various unconventional superconductors.
Related
- Intra-unit-cell Josephson scanning tunneling spectroscopy of the cuprate Bi1.2Pb0.8Sr2CaCu2O8+δ
- Atomic‐Scale Surface Imaging of Bulk Epitaxial CsPbBr₃ Perovskite Single Crystals on Mica Using Light Assisted Scanning Tunneling Microscopy at Low‐Temperature (80 K)
- Imaging the Current Distribution in Superconducting Transition-Edge Sensors with Scanning SQUID Microscopy
- Time-reversal symmetry breaking and inherent Josephson diodes in a multi-component order parameter superconductor
- Parametrized Relativistic Quantum Theory: Framework and Application to Scanning Tunneling Microscopy
BibTeX
@misc{wei2026direct,
title = {{Direct real-space imaging of sign-reversal superconducting state by scanning Josephson tunneling}},
author = {Tianheng Wei and Yanzhao Liu and Wei Ren and Zhen Liang and Ziqiang Wang and Jian Wang},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.38421},
eprint = {2610.38421},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.38421},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Direct real-space imaging of sign-reversal superconducting state by scanning Josephson tunneling
AU - Tianheng Wei
AU - Yanzhao Liu
AU - Wei Ren
AU - Zhen Liang
AU - Ziqiang Wang
AU - Jian Wang
PY - 2026
DA - 2026/10/28
PB - arXiv
DO - 10.48550/arxiv.2610.38421
UR - https://arxiv.org/abs/2610.38421
AB - Phase-sensitive experiments based on Josephson tunneling have been considered as a pivotal method to determine the pairing symmetry in high-temperature (high-Tc) cuprate superconductors. However, in iron-based superconductors, traditional phase-sensitive experiments face setbacks because of the complexity of pairing symmetry in multiband systems. Here, using scanning Josephson tunneling microscopy (SJTM), we report the half-unit-cell periodic Josephson tunneling modulations in monolayer high-Tc Fe(Te,Se) film epitaxially grown on SrTiO3(001). The Josephson tunneling almost vanishes along the lines connecting next-nearest-neighbor Fe atoms under an s-wave superconducting tip. Combined with single-particle tunneling spectra showing the full superconducting gap, our experimental results are consistent with the sign-reversal nodeless d-wave pairing symmetry. Our findings provide sub-unit-cell scale superconducting phase information for understanding the mechanism of high-Tc superconductivity. We anticipate our work as a starting point for atomically resolved Josephson interference experiments using SJTM in various unconventional superconductors.
ER -