Anomalous Hall effect and two-dimensional Fermi surfaces in the charge-density-wave state of kagome metal RbV₃Sb₅

Abstract AV₃Sb₅ (A = Cs, K, Rb) is a recently discovered superconducting system ({T}_c∼0.9–2.5 K) in which the vanadium atoms adopt the kagome structure. Intriguingly, these systems enter a charge-density-wave (CDW) phase ({T}_CDW∼80–100 K), and further evidence shows that the time-reversal symmetry is broken in the CDW phase. Concurrently, the anomalous Hall effect (AHE) has been observed in KV₃Sb₅ and CsV₃Sb₅ inside the novel CDW phase. Here, we report a comprehensive study of a high-quality RbV₃Sb₅ single crystal with magnetotransport measurements. Our data demonstrate the emergence of the AHE in RbV₃Sb₅ when the CDW state develops. The magnitude of the anomalous Hall resistivity in the low temperature limit is comparable to the reported values in KV₃Sb₅ and CsV₃Sb₅. The magnetoresistance channel further reveals a rich spectrum of quantum oscillation frequencies, many of which have not been reported before. In particular, a large quantum oscillation frequency (2235 T), which occupies ∼56% of the Brillouin zone area, was recorded. For the quantum oscillation frequencies with sufficient signal-to-noise ratio, we further perform field angle-dependent measurements, and our data indicate two-dimensional Fermi surfaces in RbV₃Sb₅. Our results provide indispensable information for understanding the AHE and band structure in kagome metal AV₃Sb₅.