Electronic structure and physical properties of the monolayer Kagome lattice system AV3Sb5 (A = K, Rb, Cs)

In this study, we employ density functional theory to investigate the electronic structure and physical properties of the monolayer Kagome lattice system of AV3Sb5 (A = K, Rb, Cs). Our results reveal that charge density wave (CDW) states are present not only in the bulk, but also in the monolayer systems. Notably, we find that the monolayer system exhibits a higher stability of the CDW states compared to the corresponding bulk system. Additionally, we find that external pressure can induce the instability of the CDW states, driving the pristine structure to a stable phase. Our band unfolding and phonon calculations also provide additional support for these findings. Our study suggests that manipulating the dimensions of Kagome lattice materials as well as applying external pressure can lead to desired physical properties, thereby paving the way for material design advancements in the family of AV3Sb5 Kagome lattice systems.