Emerging electronic states in van der Walls hetero-bilayers

Bilayer heterostructures have received tremendous attentions in recent years. It is usually believed that electronic structures of stacked van der Waals (vdW) bilayers are simply superposition of their monolayer electronic structures. Here, we show that significant interlayer electronic hybridization occurs even for the most weak-interlayer coupled MoS₂/WSe₂ bilayer among MoS₂/WSe₂ , MoSe₂/PtSe₂ and PtS₂/PtSe₂ bilayers. Several interface states originating from the interlayer S-Se or Se-Se hybridization are explicitly identified by our density functional theory calculations of up to 4000 atoms and confirmed by electrostatic force microscopy (EFM) imaging. In addition, our results also explained the found emerging states within the bandgap of the MoS₂/WSe₂ bilayer.