Structures and Physical Properties of V-Based Kagome Metals CsV_6Sb_6 and CsV_8Sb_12

We report two new members of V-based kagome metals CsV_6Sb_6 and CsV_8Sb_12. The most striking structural feature of CsV_6Sb_6 is the V kagome bilayers. For CsV_8Sb_12, there is an intergrowth of two-dimensional V kagome layers and one-dimensional V chains, and the latter ones lead to the orthorhombic symmetry of this material. Further measurements indicate that these two materials exhibit metallic and Pauli paramagnetic behaviors. More importantly, different from CsV_3Sb_5, the charge density wave state and superconductivity do not emerge in CsV_6Sb_6 and CsV_8Sb_12 when temperature is above 2 K. Small magnetoresistance with saturation behavior and linear field dependence of Hall resistivity at high field and low temperature suggest that the carriers in both materials should be uncompensated with much different concentrations. The discovery of these two new V-based kagome metals sheds light on the exploration of correlated topological materials based on kagome lattice.