Quantum Oscillations of YV₆Sn₆ and GdV₆Sn₆

Recently, materials containing kagome lattices have gained attention due to the appearance of Dirac points, van Hove singularities and geometrically driven flat bands in their resulting band structures. In particular, members of the RV₆Sn₆ (R=rare earth) subset of these materials form with pristine vanadium kagome lattices, analogous to those in the kagome based superconductor AV₃Sb₅ family, and they offer an experimental landscape to investigate the interplay of rare earth magnetism with kagome band structures. Here we present the characterization of the Fermi surfaces of both the non-magnetic member YV₆Sn₆, as well as the ferromagnetic GdV₆Sn₆, through quantum oscillations in torque magnetometry in fields up to 41.5T and temperatures down to 0.3K. The temperature and angle dependences of oscillation frequencies for YV₆Sn₆ reveal the existence of a relatively large 2D pocket (~1/2 of the area of the Brillouin Zone) with an effective mass of m*=2.5m_e, as well as small pockets (~20T) with light effective masses, approaching the quantum limit at around 25T. Similar features but with different sizes and effective masses are seen in GdV₆Sn₆, illustrating the effect of local moment magnetism on the kagome band structure.