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

Abstract

Abstract AV 3 Sb 5 (A = Cs, K, Rb) is a recently discovered superconducting system ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msub> <mml:mi>T</mml:mi> <mml:mrow> <mml:mi mathvariant="normal">c</mml:mi> </mml:mrow> </mml:msub> <mml:mo>∼</mml:mo> <mml:mn>0.9</mml:mn> </mml:math> –2.5 K) in which the vanadium atoms adopt the kagome structure. Intriguingly, these systems enter a charge-density-wave (CDW) phase ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msub> <mml:mi>T</mml:mi> <mml:mrow> <mml:mi mathvariant="normal">C</mml:mi> <mml:mi mathvariant="normal">D</mml:mi> <mml:mi mathvariant="normal">W</mml:mi> </mml:mrow> </mml:msub> <mml:mo>∼</mml:mo> <mml:mn>80</mml:mn> </mml:math> –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 KV 3 Sb 5 and CsV 3 Sb 5 inside the novel CDW phase. Here, we report a comprehensive study of a high-quality RbV 3 Sb 5 single crystal with magnetotransport measurements. Our data demonstrate the emergence of the AHE in RbV 3 Sb 5 when the CDW state develops. The magnitude of the anomalous Hall resistivity in the low temperature limit is comparable to the reported values in KV 3 Sb 5 and CsV 3 Sb 5 . 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 RbV 3 Sb 5 . Our results provide indispensable information for understanding the AHE and band structure in kagome metal AV 3 Sb 5 .