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| Main Authors: | , , , , , , , , , , , |
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| Format: | Preprint |
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2025
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| Subjects: | |
| Online Access: | https://arxiv.org/abs/2512.07272 |
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| _version_ | 1866915660297142272 |
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| author | Hu, Quanxin Zhang, Lingfeng Zheng, Yu Li, Yongwei Wang, Qiheng Liang, Xinyu Lv, Baiqing Yim, Chi-Ming Kawakami, Takuto Grinenko, Vadim Hu, Xiao Ding, Hong |
| author_facet | Hu, Quanxin Zhang, Lingfeng Zheng, Yu Li, Yongwei Wang, Qiheng Liang, Xinyu Lv, Baiqing Yim, Chi-Ming Kawakami, Takuto Grinenko, Vadim Hu, Xiao Ding, Hong |
| contents | The interplay between charge-density waves (CDWs), which break translational symmetry, and spatially homogeneous superconductivity, which breaks global U(1) gauge symmetry, can give rise to an intriguing phenomenon: the pair-density wave, characterized by a spatial modulation of the superconducting order parameter. Yet how CDWs couple to unconventional superconducting states-particularly those with time-reversal symmetry breaking (TRSB)-remains largely unexplored. Here, using scanning tunneling microscopy on heavily hole-doped Ba$_{1-x}$K$_x$Fe$_2$As$_2$, which hosts an s $\pm$ is superconducting state, we reveal a previously unobserved coupling between a surface CDW and TRSB superconductivity. Experimentally, the TRSB superconductivity imparts "chirality" to the CDW, which manifests as commensurate domains separated by domain walls with $π$-phase slips-forming what we term a bipolar CDW. The domain walls delineate TRSB domains of opposite chirality, consistent with spontaneous breaking of U(1) $\times$ Z2. Supported by theoretical modelling, we construct a framework in which a hidden interfacial pair-density modulation (PDM) mediates a linear coupling between the surface CDW and interband Josephson currents of TRSB superconductivity. Crucially, the theory shows that realizing this linear coupling requires a controlled global phase difference $δ$ $ϕ$ = $π$/2 between the PDM and CDW states. Our results uncover a previously overlooked connection between charge ordering and TRSB superconductivity, opening a pathway to explore intertwined quantum orders in iron-based superconductors and other strongly correlated systems. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2512_07272 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Novel coupling between charge order and time-reversal-symmetry-breaking superconductivity Hu, Quanxin Zhang, Lingfeng Zheng, Yu Li, Yongwei Wang, Qiheng Liang, Xinyu Lv, Baiqing Yim, Chi-Ming Kawakami, Takuto Grinenko, Vadim Hu, Xiao Ding, Hong Superconductivity The interplay between charge-density waves (CDWs), which break translational symmetry, and spatially homogeneous superconductivity, which breaks global U(1) gauge symmetry, can give rise to an intriguing phenomenon: the pair-density wave, characterized by a spatial modulation of the superconducting order parameter. Yet how CDWs couple to unconventional superconducting states-particularly those with time-reversal symmetry breaking (TRSB)-remains largely unexplored. Here, using scanning tunneling microscopy on heavily hole-doped Ba$_{1-x}$K$_x$Fe$_2$As$_2$, which hosts an s $\pm$ is superconducting state, we reveal a previously unobserved coupling between a surface CDW and TRSB superconductivity. Experimentally, the TRSB superconductivity imparts "chirality" to the CDW, which manifests as commensurate domains separated by domain walls with $π$-phase slips-forming what we term a bipolar CDW. The domain walls delineate TRSB domains of opposite chirality, consistent with spontaneous breaking of U(1) $\times$ Z2. Supported by theoretical modelling, we construct a framework in which a hidden interfacial pair-density modulation (PDM) mediates a linear coupling between the surface CDW and interband Josephson currents of TRSB superconductivity. Crucially, the theory shows that realizing this linear coupling requires a controlled global phase difference $δ$ $ϕ$ = $π$/2 between the PDM and CDW states. Our results uncover a previously overlooked connection between charge ordering and TRSB superconductivity, opening a pathway to explore intertwined quantum orders in iron-based superconductors and other strongly correlated systems. |
| title | Novel coupling between charge order and time-reversal-symmetry-breaking superconductivity |
| topic | Superconductivity |
| url | https://arxiv.org/abs/2512.07272 |