Coexistence of Surface Electronic Confinement and Topological States in Sb₄Te₃

Layered materials have attracted significant attention in recent years due to the diverse electronic properties arising from different structural variations. Here, we present angle-resolved photoemission spectroscopy measurements conducted on the topological material Sb4Te3. This material consists of a composite stacking of two distinct topological materials: the three-dimensional (3D) topological insulator Sb2Te3 and the two--dimensional (2D) topological insulator Sb2. Our angle-resolved photoemission spectroscopy measurements combined with density functional theory reveal that the topological behavior exhibited by Sb2Te3 and Sb2 persists, characterized by nontrivial topological invariant, electronic states from the spin–orbit coupling, hexagonal warping associated with time reversal symmetry and photon-energy independence in these surface states. By comparing the results with the complete bulk and surface bands, we observe parabolic states associated with the existence of stacking faults. The photon-energy independence of this state indicates confinement along the stacking direction. In essence, we revealed the existence of topological states and confined electrons in the material Sb4Te3 using angle-resolved photoemission spectroscopy experiments.