Stark effect and orbital hybridization of moiré interlayer excitons in the MoSe2/WSe2 heterobilayer

Abstract

In this paper, we undertake a theoretical investigation into the effects of both in-plane and out-of-plane static electric fields on moiré interlayer excitons (IXs) within a WSe₂/MoSe₂ heterobilayer. We thoroughly analyze a wide range of properties pertaining to the IXs, including the binding energy, Stark shift, orbital hybridization, photoluminescence (PL) spectra, and radiative lifetime. Various factors influencing IX behavior, such as the dielectric environment, spacing separation, and moiré trap effects, are examined in detail. Our results demonstrate that the in-plane electric field leads to energy splitting between states with non-zero angular momentum, such as the 2p_± dark states. Consequently, we analyze IX orbital hybridization, including hybrid Rydberg states like 1s, 2p_±, and 2s. In contrast, we show that an out-of-plane electric field induced by a double-gate setup causes a quadratic Stark effect on the center of mass (COM) eigenenergies, leading to energy splitting of degenerate states and resulting in orbital hybridization of COM eigenvectors. Additionally, we demonstrate that a parallel electric field brightens the 2p_± dark state through a one-photon PL process, due to the hybridization phenomena between s- and p-type Rydberg states. In short, our investigation is in great agreement with previous research and can assist experimenters in designing novel optoelectronic applications, such as on-chip electro-optic modulators and TeraHertz devices.