Direct view of phonon dynamics in atomically thin MoS${}_2$

Abstract

Transition metal dichalcogenide monolayers and heterostructures are highly tunable material systems that provide excellent models for physical phenomena at the two-dimensional (2D) limit. While most studies to date have focused on electrons and electron-hole pairs, phonons also play essential roles. Here, we apply ultrafast electron diffraction and diffuse scattering to directly quantify, with time and momentum resolution, electron-phonon coupling (EPC) in monolayer molybdenum disulfide (MoS${}_2$) and phonon transport from the monolayer to a silicon nitride (Si${}_3$N${}_4$) substrate. Optically generated hot carriers result in a profoundly anisotropic distribution of phonons in the monolayer on the $\sim$ 5 ps time scale. A quantitative comparison with ab-initio ultrafast dynamics simulations reveals the essential role of dielectric screening in weakening EPC. Thermal transport from the monolayer to the substrate occurs with the phonon system far from equilibrium. While screening in 2D is known to strongly affect equilibrium properties, our findings extend this understanding to the dynamic regime.

References in corpus (31)

• Advanced capabilities for materials modelling with Quantum ESPRESSO
• Coupled spin and valley physics in monolayers of MoS2 and other group-VI dichalcogenides
• Excitons in atomically thin transition metal dichalcogenides
• Optical Spectrum of MoS${}_2$: Many-body Effects and Diversity of Exciton States
• Electron-phonon interactions from first principles
• EPW: Electron-phonon coupling, transport and superconducting properties using maximally localized Wannier functions
• Valley Dependent Optoelectronics from Inversion Symmetry Breaking
• Effect of spin-orbit interaction on the excitonic effects in single-layer, double-layer, and bulk MoS2
• Valley contrasting chiral phonons in monolayer hexagonal lattices
• Transport Theory of Monolayer Transition-Metal Dichalcogenides through Symmetry
• Giant Two-Photon Absorption in Monolayer MoS2
• Valley Phonons and Exciton Complexes in a Monolayer Semiconductor
• Electron-phonon coupling and energy flow in a simple metal beyond the two-temperature approximation
• Moiré Intralayer Excitons in a MoSe${}_2$/MoS${}_2$ Heterostructure
• Direct Determination of Band Gap Renormalization in Photo-Excited Monolayer MoS2
• Mapping momentum-dependent electron-phonon coupling and non-equilibrium phonon dynamics with ultrafast electron diffuse scattering
• Momentum-Resolved View of Electron-Phonon Coupling in Multilayer WSe${}_2$
• Engineering of Neutral Excitons and Exciton Complexes in Transition Metal Dichalcogenide Monolayers through External Dielectric Screening
• Spin-orbit coupling induced valley Hall effects in transition-metal dichalcogenides
• Mechanisms of electron-phonon coupling unraveled in momentum and time: The case of soft-phonons in TiSe${}_2$
• Nonequilibrium Lattice Dynamics in Monolayer MoS2
• Enhanced electron-phonon interaction in multi-valley materials
• Accessing the anisotropic non-thermal phonon populations in black phosphorus
• Time- and momentum-resolved phonon population dynamics with ultrafast electron diffuse scattering
• Direct visualization of polaron formation in the thermoelectric SnSe
• Picosecond energy transfer in a transition metal dichalcogenide-graphene heterostructure revealed by transient Raman spectroscopy
• Larger than 80% Valley Polarization of Free Carriers in Singly-Oriented Single Layer WS${}_2$ on Au(111)
• Efficient first-principles methodology for the calculation of the all-phonon inelastic scattering in solids
• Multi-phonon diffuse scattering in solids from first-principles: Application to layered crystals and 2D materials
• Chiral valley phonons and flat phonon bands in moiré materials
• Measurements of Nonequilibrium Interatomic Forces in Photoexcited Bismuth

Cited by in corpus (13)

• Ultrafast dynamics of electrons and phonons: from the two-temperature model to the time-dependent Boltzmann equation
• Anharmonic lattice dynamics via the special displacement method
• Vibrational dichroism of chiral valley phonons
• Quantum theory of light-driven coherent lattice dynamics
• Strain-induced activation of chiral-phonon emission in monolayer WS${}_2$
• Momentum-Resolved Signatures of Carrier Screening Effects on Electron-Phonon Coupling in MoS${}_2$
• Excimer Formation in Zinc-phthalocyanine Revealed using Ultrafast Electron Diffraction
• Time-domain study of coupled collective excitations in quantum materials
• Ultrafast Phonon-Diffuse Scattering as a Tool for Observing Chiral Phonons in Monolayer Hexagonal Lattices
• Ultrafast Electron Diffuse Scattering as a Tool for Studying Phonon Transport: Phonon Hydrodynamics and Second Sound Oscillations
• Advancing Simulations of Coupled Electron and Phonon Nonequilibrium Dynamics Using Adaptive and Multirate Time Integration
• Element-specific ultrafast lattice dynamics in monolayer WSe2
• Prospects for Direct Electron Detectors in Ultrafast Electron Diffraction and Scattering Experiments