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

Abstract

AV3Sb5 (A=Cs, K, Rb) are recently discovered superconducting systems (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 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 anomalous Hall effect in RbV3Sb5 when the charge-density-wave state develops. The magnitude of anomalous Hall resistivity at 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, has been 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 anomalous Hall effect and band structure in kagome metals AV3Sb5.

Universal sublinear resistivity in vanadium kagome materials hosting charge density waves

“…kagome compounds exhibiting CDW. In Fig.4(b) we show that the exponent n = 3/5 describes the ρ(T ) behavior of KV 3 Sb 57 , RbV 3 Sb 58 , and CsV 3 Sb 5 6 samples very well above the charge ordering temperature.…”

“…The hexagonal 135 families of compounds (AV 3 Sb 5 with A= K, Rb, Cs) host curious CDWs and unconventional superconductivity tied to their vanadium kagome sheets [6][7][8][9][10][11] . Additionally, the normal states of the 135 families are identified as Z 2 topological metals with band inversion 6,10 , the CDW state shows a pair density wave 12 , nematic order 13 , and a large anomalous Hall response 14,15 in the absence of resolvable magnetic order 16 .…”

Resonant x-ray diffraction measurements in charge ordered kagome superconductors KV3Sb5 and RbV3Sb5

“…They exhibit a charge density wave (CDW) order which sets in at 80-110 K. In addition to CDW, superconductivity is observed below the transition temperature T c , which varies between ≃0.9 and ≃3.0 K for different alkali metals [1][2][3]. T c is further changed, reaching in some cases values as high as ≃7-8 K, either by doping [16] or application of pressure [17][18][19].…”