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 ( Tc∼0.9 –2.5 K) in which the vanadium atoms adopt the kagome structure. Intriguingly, these systems enter a charge-density-wave (CDW) phase ( TCDW∼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.