New publication: Two-fold symmetric superconductivity in the Kagome superconductor RbV3Sb5
Our article Two-fold symmetric superconductivity in the Kagome superconductor RbV3Sb5 was published online in Communications Physics on January 5, 2024. The study reveals a pronounced reduction of rotational symmetry inside the superconducting state of a structurally sixfold kagome material.
Why this matters
RbV3Sb5 combines a geometrically frustrated kagome lattice with charge order, nematicity, topology, and superconductivity. If the superconducting response inherits only the crystal lattice symmetry, it should remain sixfold under in-plane rotation. A robust twofold response instead signals that electronic correlations or the superconducting order itself selects a preferred direction.
Key findings
Thin-flake RbV3Sb5 devices show a strong twofold angular dependence in magnetoresistance, upper critical field, and superconducting-gap response. Near the boundary between the normal and superconducting states, a sixfold component can coexist with the dominant twofold signal, revealing how lattice symmetry and electronic symmetry breaking compete across the phase boundary.
The experiment used a vector-magnet dilution refrigerator with angular control better than 0.1 degrees. Measurements on multiple devices, changes in current direction, out-of-plane alignment checks, and alternative measurement configurations were used to rule out field misalignment, geometric effects of vortex motion, and structural artifacts. These controls establish the twofold response as an intrinsic property of the superconducting state.
LinLab’s role
Dr. Ben-Chuan LIN and Dr. Shuo WANG proposed and designed the research and performed the quantum-transport experiments. Dr. Wang and co-authors Jing-Zhi Fang and Ze-Nan Wu fabricated and characterized the devices, while complementary structural measurements supported the analysis. Dr. Lin supervised the project and led the manuscript preparation with the team. The work showcases our integrated capabilities in thin-flake fabrication, vector-field millikelvin transport, and symmetry-resolved data analysis.
Scientific significance
The observation establishes RbV3Sb5 as a platform for studying correlation-driven rotational symmetry breaking and unconventional superconductivity. It also provides the symmetry foundation for our later work on time-reversal-symmetry-breaking hysteresis and pseudo-spin-polarized pairing, linking several LinLab studies into a coherent research program.