Ultrafast phonon-driven charge transfer in van der Waals heterostructures

Abstract

Van der Waals heterostructures built by vertically stacked transition metal dichalcogenides (TMDs) exhibit a rich energy landscape including interlayer and intervalley excitons. Recent experiments demonstrated an ultrafast charge transfer in TMD heterostructures. However, the nature of the charge transfer process has remained elusive. Based on a microscopic and material-realistic exciton theory, we reveal that phonon-mediated scattering via strongly hybridized intervalley excitons governs the charge transfer process that occurs on a sub-100fs timescale. We track the time-, momentum-, and energy-resolved relaxation dynamics of optically excited excitons and determine the temperature- and stacking-dependent charge transfer time for different TMD bilayers. The provided insights present a major step in microscopic understanding of the technologically important charge transfer process in van der Waals heterostructures.

References in corpus (13)

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• Tightly bound excitons in monolayer WSe2
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• Ultrafast transition between exciton phases in van der Waals heterostructures
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• Hybridized intervalley moiré excitons and flat bands in twisted WSe${}_2$ bilayers
• Intrinsic Lifetime of Higher Excitonic States in Tungsten Diselenide Monolayers
• Optical dipole orientation of interlayer excitons in MoSe${}_2$-WSe${}_2$ heterostacks
• Interlayer exciton valley polarization dynamics in large magnetic fields

Cited by in corpus (14)

• Exciton optics, dynamics and transport in atomically thin semiconductors
• Interface engineering of charge-transfer excitons in 2D lateral heterostructures
• Ultrafast dynamics of bright and dark excitons in monolayer WSe${}_2$ and heterobilayer WSe${}_2$/MoS${}_2$
• Bosonic Delocalization of Dipolar Moiré Excitons
• Probing correlations in the exciton landscape of a moiré heterostructure
• Impact of atomic reconstruction on optical spectra of twisted TMD homobilayers
• Ultrafast nano-imaging of dark excitons
• Probing excitons with time-resolved momentum microscopy
• Optical Signatures of Moiré Trapped Biexcitons
• Direct visualization of hybrid excitons in van der Waals heterostructures
• Excitonic thermalization bottleneck in twisted TMD heterostructures
• Hybrid Frenkel-Wannier excitons facilitate ultrafast energy transfer at a 2D-organic interface
• Review: Advanced characterization of the spatial variation of moiré heterostructures and moiré excitons
• Two dimensional semiconductors: optical and electronic properties