Direct measurement of key exciton properties: energy, dynamics and spatial distribution of the wave function

Abstract

Excitons, Coulomb-bound electron-hole pairs, are the fundamental excitations governing the optoelectronic properties of semiconductors. While optical signatures of excitons have been studied extensively, experimental access to the excitonic wave function itself has been elusive. Using multidimensional photoemission spectroscopy, we present a momentum-, energy- and time-resolved perspective on excitons in the layered semiconductor WSe${}_2$. By tuning the excitation wavelength, we determine the energy-momentum signature of bright exciton formation and its difference from conventional single-particle excited states. The multidimensional data allows to retrieve fundamental exciton properties like the binding energy and the exciton-lattice coupling and to reconstruct the real-space excitonic distribution function via Fourier transform. All quantities are in excellent agreement with microscopic calculations. Our approach provides a full characterization of the exciton properties and is applicable to bright and dark excitons in semiconducting materials, heterostructures and devices.

References in corpus (20)

• Control of valley polarization in monolayer MoS2 by optical helicity
• Valley polarization in MoS2 monolayers by optical pumping
• Exciton Binding Energy and Nonhydrogenic Rydberg Series in Monolayer WS2
• Excitons in atomically thin transition metal dichalcogenides
• Measurement of the optical dielectric function of transition metal dichalcogenide monolayers: MoS2, MoSe2, WS2 and WSe2
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• Excitonic linewidth and coherence lifetime in monolayer transition metal dichalcogenides
• Electronic and Thermoelectric Properties of Few-Layer Transition Metal Dichalcogenides
• Directly visualizing the momentum forbidden dark excitons and their dynamics in atomically thin semiconductors
• Excitons versus electron-hole plasma in monolayer transition metal dichalcogenide semiconductors
• {\it Ab--initio} finite temperature excitons
• Generation and evolution of spin-, valley- and layer-polarized excited carriers in inversion-symmetric WSe2
• Phonon Sidebands in Transition Metal Dichalcogenides
• Time- and angle-resolved photoemission spectroscopy of solids in the extreme ultraviolet at 500 kHz repetition rate
• Optically discriminating carrier-induced quasiparticle band gap and exciton energy renormalization in monolayer MoS2
• Revealing Hidden Orbital Pseudospin Texture with Time-Reversal Dichroism in Photoelectron Angular Distributions
• First-principles approach to excitons in time-resolved and angle-resolved photoemission spectra
• Photoemission signature of excitons
• Theory of exciton dynamics in time-resolved ARPES: intra- and intervalley scattering in two-dimensional semiconductors
• Efficient orbital imaging based on ultrafast momentum microscopy and sparsity-driven phase retrieval

Cited by in corpus (44)

• Formation of moiré interlayer excitons in space and time
• Time- and Angle-Resolved Photoemission Studies of Quantum Materials
• Angle-resolved photoemission spectroscopy
• Exciton optics, dynamics and transport in atomically thin semiconductors
• Nonclassical Exciton Diffusion in Monolayer WSe2
• Real-time GW: Toward an ab initio description of the ultrafast carrier and exciton dynamics in two-dimensional materials
• Time-domain observation of interlayer exciton formation and thermalization in a MoSe${}_2$/WSe${}_2$ heterostructure
• Phonon-assisted inter-valley scattering determines ultrafast exciton dynamics in MoSe${}_2$ bilayers
• Ultrafast dynamics of bright and dark excitons in monolayer WSe${}_2$ and heterobilayer WSe${}_2$/MoS${}_2$
• Polarization-Modulated Angle-Resolved Photoemission Spectroscopy: Towards Circular Dichroism without Circular Photons and Bloch Wavefunction Reconstruction
• Exciton-Driven Renormalization of Quasiparticle Band Structure in Monolayer MoS2
• Exciton-phonon interaction calls for a revision of the "exciton" concept
• Photo-induced nonequilibrium states in Mott insulators
• Excitons and carriers in transient absorption and time-resolved ARPES spectroscopy: an abinitio approach
• Probing correlations in the exciton landscape of a moiré heterostructure
• Detecting light-induced Floquet band gaps of graphene via trARPES
• Impact of dark excitons on Förster type resonant energy transfer between dye molecules and atomically thin semiconductors
• Multiorbital exciton formation in an organic semiconductor
• Berry Curvature Signatures in Chiroptical Excitonic Transitions
• High-harmonic spectroscopy of strongly bound excitons in solids
• Twisted MoSe2 Homobilayer Behaving as a Heterobilayer
• Ultrafast Hidden Spin Polarization Dynamics of Bright and Dark Excitons in 2H-WSe${}_2$
• Spin- and time-resolved photoelectron spectroscopy and diffraction studies using time-of-flight momentum microscopes
• Ultrafast Momentum-resolved Hot Electron Dynamics in the Two-dimensional Topological Insulator Bismuthene
• Probing excitons with time-resolved momentum microscopy
• Direct visualization of hybrid excitons in van der Waals heterostructures
• Impact of optically pumped non-equilibrium steady states on luminescence emission of atomically-thin semiconductor excitons
• Excitonic Bloch equations from first principles
• Probing magnetic orbitals and Berry curvature with circular dichroism in resonant inelastic X-ray scattering
• High harmonic generation light source with polarization selectivity and sub-100-$\mu$m beam size for time- and angle-resolved photoemission spectroscopy
• 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
• Valley-exchange coupling probed by angle-resolved photoluminescence
• Dipolar interactions enhanced by two-dimensional dielectric screening in few-layer van der Waals structures
• Coupled exciton internal and center-of-mass motions in two-dimensional semiconductors by a periodic electrostatic potential
• Twistronics and moiré superlattice physics in 2D transition metal dichalcogenides
• External screening and lifetime of exciton population in single-layer ReSe${}_2$ probed by time- and angle-resolved photoemission spectroscopy
• A New Era of Quantum Materials Mastery and Quantum Simulators In and Out of Equilibrium
• Element-specific ultrafast lattice dynamics in monolayer WSe2
• Observation of quasi-steady dark excitons and gap phase in a doped semiconductor
• Excited-state band structure mapping
• Observing the spatial and temporal evolution of exciton wave functions
• Excitonic effects in the photocarriers dynamics of two-dimensional materials
• Ultrafast Charge Transfer Dynamics at the MoS${}_2$/Au Interface Observed via Optical Spectroscopy under Ambient Conditions