Emergence of large quantum oscillation frequencies in thin flakes of the kagome superconductor CsV3Sb5

• DOI: 10.1103/physrevb.106.195103
• Publication Date: 2022-11-02T14:04:05Z
• Authors: W. Zhang; Lingfei Wang; Chun Wai Tsang; Xinyou Liu; Jianyu Xie; Wing Chi Yu; Kwing To Lai; Swee K. Goh
• Keywords: Brillouin zone

Kagome metals AV$_3$Sb$_5$~(A = K, Rb, Cs) are recently discovered platforms featuring an unusual charge-density-wave (CDW) order and superconductivity. The electronic band structure of a kagome lattice can host both flat bands as well Dirac-like bands, offering the possibility to stabilize various quantum states. Here, we probe CsV$_3$Sb$_5$ via Shubnikov-de Haas oscillations on bulk single crystals thin flakes. Although our frequency spectra broadly consistent with published data, unambiguously reveal existence new frequencies large ranging from $\sim$2085~T $\sim$2717~T in flakes when magnetic field is along $c$-axis. These quasi-two-dimensional correspond $\sim$52\% 67\% CDW-distorted Brillouin zone volume. Lifshitz-Kosevich analysis further uncovers surprisingly small cyclotron effective masses, $\sim$0.1~$m_e$, for these frequencies. Consequently, number high-velocity carriers exists flake CsV$_3$Sb$_5$. Comparing calculations, argue that orbital-selective modification active. Our results provide indispensable information understanding fermiology CsV$_3$Sb$_5$, paving way how mechanism become means tune its properties.