Ultrafast nano-imaging of dark excitons
arXiv:2305.18908 · doi:10.1038/s41566-024-01568-y
Abstract
The role and impact of spatial heterogeneity in two-dimensional quantum materials represents one of the major research quests regarding the future application of these materials in optoelectronics and quantum information science. In the case of transition-metal dichalcogenide heterostructures, in particular, direct access to heterogeneities in the dark-exciton landscape with nanometer spatial and ultrafast time resolution is highly desired, but remains largely elusive. Here, we introduce ultrafast dark field momentum microscopy to spatio-temporally resolve dark exciton formation dynamics in a twisted WSe/MoS heterostructure with 55 femtosecond time- and 500~nm spatial resolution. This allows us to directly map spatial heterogeneity in the electronic and excitonic structure, and to correlate these with the dark exciton formation and relaxation dynamics. The benefits of simultaneous ultrafast nanoscale dark-field momentum microscopy and spectroscopy is groundbreaking for the present study, and opens the door to new types of experiments with unprecedented spectroscopic and spatiotemporal capabilities.
39 pages, 4 main figures, 8 supplemental figures
References in corpus (21)
- Cross-sectional imaging of individual layers and buried interfaces of graphene-based heterostructures and superlattices
- Quasiparticle band structures and optical properties of strained monolayer MoS2 and WS2
- Van der Waals heterostructures for high-performance device applications: challenges and opportunities
- Intrinsic Transport Properties of Electrons and Holes in Monolayer Transition Metal Dichalcogenides
- Probing the influence of dielectric environment on excitons in monolayer WSe2: Insight from high magnetic fields
- Dark excitons in transition metal dichalcogenides
- Excitons versus electron-hole plasma in monolayer transition metal dichalcogenide semiconductors
- Interlayer coupling in commensurate and incommensurate bilayer structures of transition metal dichalcogenides
- Environmentally-Sensitive Theory of Electronic and Optical Transitions in Atomically-Thin Semiconductors
- Programming moiré patterns in 2D materials by bending
- Hybridized intervalley moiré excitons and flat bands in twisted WSe bilayers
- Exciton optics, dynamics and transport in atomically thin semiconductors
- Orbital-resolved Observation of Singlet Fission
- Exciton landscape in van der Waals heterostructures
- Momentum-Resolved Exciton Coupling and Valley Polarization Dynamics in Monolayer WS
- Ultrafast dynamics of bright and dark excitons in monolayer WSe and heterobilayer WSe/MoS
- Ultrafast phonon-driven charge transfer in van der Waals heterostructures
- Probing correlations in the exciton landscape of a moiré heterostructure
- Multiorbital exciton formation in an organic semiconductor
- Direct visualization of hybrid excitons in van der Waals heterostructures
- Photoemission orbital tomography for excitons in organic molecules