Tuning topological properties in Bi₂Se₃/VSe₂ heterostructures

Topological materials have drawn great attention due to their exotic physical properties and various applications in quantum information science. Central to the fundament research and practical applications are the control and tunability of the topological states through material engineering, such as doping, strain and stacking of different 2D van der Waals materials. Here we present a combined angle-resolved photoemission spectroscopy (ARPES) and first-principles study of the topological properties of few-layer 1T VSe₂ on few-quintuple layer Bi₂Se₃ heterojunctions. ARPES measurements show that details of the topological band structure of the heterojunction strongly depend on the thickness of the quintuple layers of Bi₂Se₃. Density functional theory is used to interpret the ARPES measurement and understand the evolution of the topological states. This study gains insights into the topological properties of VSe₂/ Bi₂Se₃ heterojunctions, which have important implications on tunability of the topological materials.