New publication: Unconventional hysteresis due to time-reversal symmetry breaking superconductivity in RbV3Sb5
Our article Unconventional hysteresis due to time-reversal symmetry breaking superconductivity in RbV3Sb5 was published online in Nature Communications on January 17, 2026. The work provides transport evidence that superconductivity in thin-flake RbV3Sb5 breaks time-reversal symmetry.
Why this matters
Kagome metals host an unusually rich combination of charge order, nematicity, topology, and superconductivity. A central question is whether their superconducting state is conventional or carries an additional internal degree of freedom that can spontaneously break symmetry. Establishing time-reversal symmetry breaking is especially challenging because magnetic hysteresis can also arise from trapped flux, vortex motion, heating, or other extrinsic effects.
Key findings
Using thin-flake RbV3Sb5 devices, we observed a reproducible in-plane magnetoresistance hysteresis that depends on the magnetic-field sweep direction. The response is qualitatively different from conventional vortex-related hysteresis and is absent in CsV3Sb5 devices measured under comparable conditions, providing an important material-specific control.
Two further observations strengthen the conclusion. At a fixed magnetic field, a finite-resistance state can be reset into the zero-resistance superconducting state by applying and then removing a large current. Around 400 mK, superconductivity also re-enters during a continuous field sweep. Together with the two-fold superconducting response, these results point to multiple superconducting domains and an intrinsically time-reversal-symmetry-breaking order parameter.
LinLab’s role
Dr. Ben-Chuan LIN supervised the project and conceived and designed the experiments. Dr. Shuo WANG and Dr. Lin performed the quantum-transport measurements, while Dr. Wang and co-author Jing-Zhi Fang led device fabrication and sample characterization. The team also carried out control measurements and cross-material comparisons to distinguish the intrinsic superconducting response from experimental artifacts. Dr. Lin co-led the interpretation and manuscript preparation.
Collaboration and outlook
The experimental program was complemented by theoretical work from Professor Kam Tuen Law’s group at the Hong Kong University of Science and Technology. Academician Dapeng YU also contributed to project supervision. The resulting connection between experiment and theory narrows the possible pairing symmetries in RbV3Sb5 and establishes a foundation for phase-sensitive probes of superconducting domains, boundary states, and topological superconductivity in kagome materials.