Tuning Topological Phase Transitions of 2D Chern Insulators by Chemical Substitution

Van der Waals Antiferromagnets (AFMs) have drawn significant attention due to their potential in spintronics device applications. Recently synthesized layered AFM UOTe has been identified as a strongly correlated material that exhibits a Dirac semimetal phase in its bulk form and transitions into an AFM Chern insulator at bilayer. The purpose of this study is to examine the differences in electronic band structures and topological properties of the sister compounds, namely, UOSe and UOS by employing density functional theory (DFT) calculation. We found that the chalcogen elements (Te, Se, S) in uranium compounds significantly impact their electronic structures and topological properties. For example, in UOSe, we predict the band inversion around the Γ point is much cleaner. However, the system becomes topologically trivial. Further investigations are ongoing to understand the mechanism of this topological phase transition. We are currently investigating the electronic structure of UOS, which will enable us to gain a deeper understanding of how the band structure changes with lighter chalcogens.