Interplay between Anomalous Metallic and Superconducting States Tuned by Disorder in Thin Flakes of Kagome Metal KV3Sb5

Recently V-based Kagome metal attracted intense attention due to the coexistence of topological nontrivial electronic structure, charge density wave, and superconductivity. Here we report the fabrication and physical investigations of the single-crystalline thin flakes of the Kagome metal KV3Sb5. For the samples with the effective superconducting thickness of 7±2 nm, the Berezinskii-Kosterlitz-Thouless type behavior is revealed by the temperature dependent resistance and voltage-current data, which indicates the presence of two-dimensional superconductivity. Meanwhile, the temperature-independent resistance is observed in a wide field region, supplying the hallmark of the anomalous metallic state. Importantly, by comparing the interplay between the superconducting and anomalous metallic states of two samples with different levels of disorder, a striking competitive evolution with the external field between these two states is uncovered.