Spectroscopic signals of excitons in monolayer MnBi₂Te₄

MnBi₂Te₄ (MBT) continues to attract significant attention as a magnetic topological material, exhibiting phenomena such as antiferromagnetism, the quantum anomalous Hall effect, axion insulating behavior, and nontrivial quantum geometry. Owing to its van der Waals nature, MBT is highly sensitive to dimensional confinement, with layer thickness playing a decisive role in its electronic and magnetic properties. In this work, we present time- and angle-resolved photoemission (trARPES) evidence for excitonic states in molecular beam epitaxy–grown monolayer MBT. Although a single septuple-layer MBT is topologically trivial within the noninteracting band picture, it lies near the topological phase boundary observed in multilayer MBT. This proximity makes monolayer MBT a promising platform to explore the interplay between excitonic correlations, magnetism, and topological band inversion in reduced dimensions.