Moir\'e lattice-induced formation and tuning of hybrid dipolar excitons in twisted WS$_2$/MoSe$_2$ heterobilayers

TL;DR

This study demonstrates how tuning the twist angle in WS₂/MoSe₂ heterobilayers modulates moiré lattice-induced hybrid excitons, revealing new quantum states and enabling control over excitonic properties in twisted 2D semiconductors.

Contribution

It reports the first wide-range tuning of moiré lattice in WS₂/MoSe₂ bilayers, showing continuous control of interlayer excitons and their hybridization with intralayer excitons, including revival phenomena near specific angles.

Findings

Moiré lattice tuning affects hybrid exciton energies.

Revival of hybrid excitons near 21.8° and 38.2° twist angles.

Determination of interlayer exciton effective mass and tunneling strength.

Abstract

Moir\'e superlattices formed in van der Waals bilayers have enabled the creation and manipulation of new quantum states, as is exemplified by the discovery of superconducting and correlated insulating states in twisted bilayer graphene near the magic angle. Twisted bilayer semiconductors may lead to tunable exciton lattices and topological states, yet signatures of moir\'e excitons have been reported only in closely angularly-aligned bilayers. Here we report tuning of moir\'e lattice in WS$_{2}$ /MoSe$_{2}$ bilayers over a wide range of twist angles, leading to the continuous tuning of moir\'e lattice induced interlayer excitons and their hybridization with optically bright intralayer excitons. A pronounced revival of the hybrid excitons takes place near commensurate twist angles, 21.8{\deg}and 38.2{\deg}, due to interlayer tunneling between states connected by a moir\'e reciprocal lattice vector. From the angle dependence, we obtain the effective mass of the interlayer excitons and the electron inter-layer tunneling strength. These findings pave the way for understanding and engineering rich moir\'e-lattice induced phenomena in angle-twisted semiconductor van dar Waals heterostructures.