Van der Waals heterostructures show fascinating physics including trapped moire exciton states, anomalous moire exciton transport, generalized Wigner crystals, etc. Bilayers of transition metal dichalcogenides (TMDs) are characterized by long-lived spatially separated interlayer excitons. Provided a strong interlayer tunneling, hybrid exciton states consisting of interlayer and intralayer excitons can be formed. Here, electrons and/or holes are in a superposition of both layers. Although crucial for optics, dynamics, and transport, hybrid excitons are usually optically inactive and have therefore not been directly observed yet. Based on a microscopic and material-specific theory, we show that time- and angle-resolved photoemission spectroscopy (tr-ARPES) is the ideal technique to directly visualize these hybrid excitons. Concretely, we predict a characteristic double-peak ARPES signal arising from the hybridized hole in the MoS2 homobilayer. The relative intensity is proportional to the quantum mixture of the two hybrid valence bands at the Γ point. Due to the strong hybridization, the peak separation of more than 0.5 eV can be resolved in ARPES experiments. Our study provides a concrete recipe of how to directly visualize hybrid excitons and how to distinguish them from the usually observed regular excitonic signatures.
@article{arxiv.2305.03437,
title = {Direct visualization of hybrid excitons in van der Waals heterostructures},
author = {Giuseppe Meneghini and Marcel Reutzel and Stefan Mathias and Samuel Brem and Ermin Malic},
journal= {arXiv preprint arXiv:2305.03437},
year = {2023}
}