Electronic Structural Moiré Pattern Effects on MoS₂/MoSe₂ 2D Heterostructures

TLDR

The authors predict that interlayer coupling in MoS₂/MoSe₂ bilayers places the valence‑band maximum at the Γ point and that such wave‑function localization is a general feature of 2D van der Waals heterostructures, potentially affecting carrier mobility and optical properties. First‑principles calculations and a 6630‑atom Moiré supercell using a linear‑scaling three‑dimensional fragment method were employed to analyze the electronic structures of various stacking configurations in MoS₂/MoSe₂ bilayers. The study finds that weak van der Waals interactions prevent lattice‑matched coherence, leading to a nanometer‑scale Moiré pattern, with the VBM strongly localized at Γ and the CBM weakly localized at the MoS₂ K point.

Abstract

The structural and electronic properties of MoS2/MoSe2 bilayers are calculated using first-principles methods. It is found that the interlayer van der Waals interaction is not strong enough to form a lattice-matched coherent heterostructure. Instead, a nanometer-scale Moiré pattern structure will be formed. By analyzing the electronic structures of different stacking configurations, we predict that the valence-band maximum (VBM) state will come from the Γ point due to interlayer electronic coupling. This is confirmed by a direct calculation of a Moiré pattern supercell containing 6630 atoms using the linear scaling three-dimensional fragment method. The VBM state is found to be strongly localized, while the conduction band minimum (CBM) state is only weakly localized, and it comes from the MoS2 layer at the K point. We predict such wave function localization can be a general feature for many two-dimensional (2D) van der Waals heterostructures and can have major impacts on the carrier mobility and other electronic and optical properties.