Intrinsic Electric Fields Promote Delocalized Interlayer Excitons in Janus In2SSe Moiré Bilayers

Abstract

The moiré potential in van der Waals (vdW) moiré superlattices is well-established to significantly influence electronic structures and optical excitations. When Janus monolayers are employed to construct twisted bilayers, an additional degree of freedom─the out-of-plane Janus field─is introduced alongside the moiré potential, leading to modifications in both electronic and optical properties. While these two effects have been individually investigated in prior studies on excitons, the behavior of excitons under the simultaneous presence of both effects remained unexplored. In this study, we investigate, for the first time, the interplay between these two effects in twisted Janus In₂SSe. Our results demonstrate that the band structures and excitonic properties can be significantly modulated through variations in stacking sequences and intrinsic dipole orientations. This work provides a framework for the precise control of emission energy, exciton characteristics, and the spatial distribution of moiré excitons. We predict the coexistence of intrinsic Janus field-induced interlayer excitons and moiré potential-driven moiré excitons in twisted bilayer Janus In₂SSe. These findings not only elucidate the interaction between Janus fields and moiré potentials but also introduce a novel, multifaceted strategy for exciton manipulation.