Pair-mixing induced Time-reversal-breaking superconductivity
Abstract
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-TaS or chiral molecule intercalated TaS hybrid superlattices, and is regarded as evidence of emergent chiral superconductivity. However, the of these TMD superconductors is of the same order as pristine 1H or 2H-TaS, 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 superlattices.
Cite
@article{arxiv.2511.04629,
title = {Pair-mixing induced Time-reversal-breaking superconductivity},
author = {Saswata Mandal and Chao-Xing Liu},
journal= {arXiv preprint arXiv:2511.04629},
year = {2025}
}
Comments
42 pages, 7 figures