Observation of Cooper-pair density modulation state
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arXiv
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| Autori principali: | , , , , , , , , , , |
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| Natura: | Preprint |
| Pubblicazione: |
2024
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| _version_ | 1866910411791532032 |
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| author | Kong, Lingyuan Papaj, Michał Kim, Hyunjin Zhang, Yiran Baum, Eli Li, Hui Watanabe, Kenji Taniguchi, Takashi Gu, Genda Lee, Patrick A. Nadj-Perge, Stevan |
| author_facet | Kong, Lingyuan Papaj, Michał Kim, Hyunjin Zhang, Yiran Baum, Eli Li, Hui Watanabe, Kenji Taniguchi, Takashi Gu, Genda Lee, Patrick A. Nadj-Perge, Stevan |
| contents | Superconducting states that break space-group symmetries of the underlying crystal can exhibit nontrivial spatial modulation of the order parameter. Previously, such remarkable states were intimately associated with the breaking of translational symmetry, giving rise to the density-wave orders, with wavelengths spanning several unit cells. However, a related basic concept has been long overlooked: when only intra-unit-cell symmetries of the space group are broken, the superconducting states can display a distinct type of nontrivial modulation preserving long-range lattice translation. Here, we refer to this new concept as the pair density modulation (PDM), and report the first observation of a PDM state in exfoliated thin flakes of iron-based superconductor FeTe$_{\text{0.55}}$Se$_{\text{0.45}}$. Using scanning tunneling microscopy, we discover robust superconducting gap modulation with the wavelength corresponding to the lattice periodicity and the amplitude exceeding 30% of the gap average. Importantly, we find that the observed modulation originates from the large difference in superconducting gaps on the two nominally equivalent iron sublattices. The experimental findings, backed up by model calculations, suggest that in contrast to the density-wave orders, the PDM state is driven by the interplay of sublattice symmetry breaking and a peculiar nematic distortion specific to the thin flakes. Our results establish new frontiers for exploring the intertwined orders in strong-correlated electronic systems and open a new chapter for iron-based superconductors. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2404_10046 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | Observation of Cooper-pair density modulation state Kong, Lingyuan Papaj, Michał Kim, Hyunjin Zhang, Yiran Baum, Eli Li, Hui Watanabe, Kenji Taniguchi, Takashi Gu, Genda Lee, Patrick A. Nadj-Perge, Stevan Superconductivity Strongly Correlated Electrons Superconducting states that break space-group symmetries of the underlying crystal can exhibit nontrivial spatial modulation of the order parameter. Previously, such remarkable states were intimately associated with the breaking of translational symmetry, giving rise to the density-wave orders, with wavelengths spanning several unit cells. However, a related basic concept has been long overlooked: when only intra-unit-cell symmetries of the space group are broken, the superconducting states can display a distinct type of nontrivial modulation preserving long-range lattice translation. Here, we refer to this new concept as the pair density modulation (PDM), and report the first observation of a PDM state in exfoliated thin flakes of iron-based superconductor FeTe$_{\text{0.55}}$Se$_{\text{0.45}}$. Using scanning tunneling microscopy, we discover robust superconducting gap modulation with the wavelength corresponding to the lattice periodicity and the amplitude exceeding 30% of the gap average. Importantly, we find that the observed modulation originates from the large difference in superconducting gaps on the two nominally equivalent iron sublattices. The experimental findings, backed up by model calculations, suggest that in contrast to the density-wave orders, the PDM state is driven by the interplay of sublattice symmetry breaking and a peculiar nematic distortion specific to the thin flakes. Our results establish new frontiers for exploring the intertwined orders in strong-correlated electronic systems and open a new chapter for iron-based superconductors. |
| title | Observation of Cooper-pair density modulation state |
| topic | Superconductivity Strongly Correlated Electrons |
| url | https://arxiv.org/abs/2404.10046 |