When van der Waals Met Kagome: A 2D Antimonide with a Vanadium-Kagome Network.

2D materials showcase unconventional properties emerging from quantum confinement effects. In this work, a "soft chemical" route allows for the deintercalation of K from the layered antimonide KVSb, resulting in the discovery of a new metastable 2D-Kagome antimonide KVSb with a van der Waals gap of 3.2 Å. The structure of KVSb was determined via the synergistic techniques, including X-ray pair distribution function analysis, advanced transmission electron microscopy, and density functional theory calculations. The KVSb compound crystallizes in the monoclinic space group 2/ ( = 9.57(2) Å, = 5.502(8) Å, = 10.23(2) Å, β = 97.6(2)°, = 2). The [VSb] layers in KVSb are retained upon deintercalation and closely resemble the layers in the parent compound, yet deintercalation results in a relative shift of the adjacent [VSb] layers. The magnetic properties of the KVSb phase in the 2-300 K range are comparable to those of KVSb and another Kagome antimonide KVSb, consistent with nearly temperature-independent paramagnetism. Electronic band structure calculation suggests a nontrivial band topology with flat bands and opening of band crossing afforded by deintercalation. Transport property measurements reveal a metallic nature for KVSb and a low thermal conductivity of 0.6 W K m at 300 K. Additionally, ion exchange in KVSb via a solvothermal route leads to a successful partial exchange of K with ( = Na, Rb, and Cs). This study highlights the tunability of the layered structure of the KVSb compound, providing a rich playground for the realization of new 2D materials.