Fermi surface mapping of the kagome superconductor RbV3Sb5 using de Haas-van Alphen oscillations

We present the results from torque magnetometry studies of the kagome superconductor RbV3Sb5 under applied fields up to 45 T and temperatures down to liquid 3He temperature (0.32 K). The torque signal shows clear de Haas-van Alphen (dHvA) oscillations with eight distinct frequencies ranging from approximate to 150 to 3000 T. Among these, five are above 500 T. Angle-dependent measurement of dHvA oscillations shows that all frequencies follow 1/cos theta dependence, where theta is the tilt angle with respect to the applied field direction, and the oscillations disappear above theta = 60 degrees, which confirms that the Fermi surfaces corresponding to these frequencies are two dimensional. The Berry phase (phi), calculated by constructing a Landau level fan diagram, is found to be approximate to it, which strongly supports the nontrivial topology of RbV3Sb5. Using the Lifshitz-Kosevich formula, we estimate the effective mass (m*) of charge carriers in RbV3Sb5, and it is found to be heavier (approximate to 0.7mo, where mo is the free electron mass) than that for other topological insulators. The findings of high frequencies up to 3000 Tin RbV3Sb5 have not been reported previously, and the results regarding the Fermi surface of RbV3Sb5 are crucial for understanding the charge density wave order, superconductivity, and nontrivial topology in AV3Sb5 (A = K, Rb, and Cs), as well as the interplay among them.