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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/2511.04629 |
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| _version_ | 1866912716019466240 |
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| author | Mandal, Saswata Liu, Chao-Xing |
| author_facet | Mandal, Saswata Liu, Chao-Xing |
| contents | Experimental evidences of spontaneous time-reversal (TR) symmetry breaking have been reported for the superconducting ground state in the transition metal dichalcogenide (TMD) superconductor 4H$_b$-TaS$_2$ or chiral molecule intercalated TaS$_2$ hybrid superlattices, and is regarded as evidence of emergent chiral superconductivity. However, the $T_c$ of these TMD superconductors is of the same order as pristine 1H or 2H-TaS$_2$, which do not show any signature of TR breaking and are believed to be conventional Bardeen-Cooper-Schrieffer superconductors. To resolve this puzzle, we propose a new type of pair-mixing state that mixes the dominant conventional s-wave pairing channel with the subdominant chiral p-wave pairing channel via a finite Cooper-pair momentum, based on symmetry analysis within the Ginzburg-Landau theory. Our analysis shows that the fourth-order terms in the chiral p-wave channel can lead to a variety of pair-mixing states with spontaneous TR breaking. These TR-breaking superconducting states also reveal a zero-field, junction-free superconducting diode effect that is observed in chiral molecule intercalated TaS$_2$ superlattices. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2511_04629 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Pair-mixing induced Time-reversal-breaking superconductivity Mandal, Saswata Liu, Chao-Xing Superconductivity Experimental evidences of spontaneous time-reversal (TR) symmetry breaking have been reported for the superconducting ground state in the transition metal dichalcogenide (TMD) superconductor 4H$_b$-TaS$_2$ or chiral molecule intercalated TaS$_2$ hybrid superlattices, and is regarded as evidence of emergent chiral superconductivity. However, the $T_c$ of these TMD superconductors is of the same order as pristine 1H or 2H-TaS$_2$, which do not show any signature of TR breaking and are believed to be conventional Bardeen-Cooper-Schrieffer superconductors. To resolve this puzzle, we propose a new type of pair-mixing state that mixes the dominant conventional s-wave pairing channel with the subdominant chiral p-wave pairing channel via a finite Cooper-pair momentum, based on symmetry analysis within the Ginzburg-Landau theory. Our analysis shows that the fourth-order terms in the chiral p-wave channel can lead to a variety of pair-mixing states with spontaneous TR breaking. These TR-breaking superconducting states also reveal a zero-field, junction-free superconducting diode effect that is observed in chiral molecule intercalated TaS$_2$ superlattices. |
| title | Pair-mixing induced Time-reversal-breaking superconductivity |
| topic | Superconductivity |
| url | https://arxiv.org/abs/2511.04629 |