Strain-dependent exciton diffusion in transition metal dichalcogenides

Abstract

Monolayers of transition metal dichalcogenides (TMDs) have a remarkable excitonic landscape with deeply bound bright and dark exciton states. Their properties are strongly affected by lattice distortions that can be created in a controlled way via strain. Here, we perform a joint theory-experiment study investigating exciton diffusion in strained tungsten disulfide (WS${}_2$) monolayers. We reveal a non-trivial and non-monotonic influence of strain. Lattice deformations give rise to different energy shifts for bright and dark excitons changing the excitonic landscape, the efficiency of intervalley scattering channels, and the weight of single exciton species to the overall exciton diffusion. We predict a minimal diffusion coefficient in unstrained WS${}_2$ followed by a steep speed-up by a factor of 3 for tensile biaxial strain at about 0.6\% strain - in excellent agreement with our experiments. The obtained microscopic insights on the impact of strain on exciton diffusion are applicable to a broad class of multi-valley 2D materials.

arXiv comment8 pages, 4 figures, supplementary info (10 pages, 5 figures)

References in corpus (39)

• Atomically thin MoS2: A new direct-gap semiconductor
• Exciton Binding Energy and Nonhydrogenic Rydberg Series in Monolayer WS2
• Bandgap Engineering of Strained Monolayer and Bilayer MoS2
• Excitons in atomically thin transition metal dichalcogenides
• k.p theory for two-dimensional transition metal dichalcogenide semiconductors
• Experimental demonstration of continuous electronic structure tuning via strain in atomically thin MoS2
• Exciton physics and device application of two-dimensional transition metal dichalcogenide semiconductors
• Large-scale quantum-emitter arrays in atomically thin semiconductors
• Deterministic strain-induced arrays of quantum emitters in a two-dimensional semiconductor
• Excitonic linewidth and coherence lifetime in monolayer transition metal dichalcogenides
• Intrinsic Transport Properties of Electrons and Holes in Monolayer Transition Metal Dichalcogenides
• Exciton diffusion and halo effects in monolayer semiconductors
• Momentum-space indirect interlayer excitons in transition metal dichalcogenide van der Waals heterostructures
• Biaxial strain tuning of the optical properties of single-layer transition metal dichalcogenides
• Transport Theory of Monolayer Transition-Metal Dichalcogenides through Symmetry
• Ultrafast transition between exciton phases in van der Waals heterostructures
• Dark excitons in transition metal dichalcogenides
• Fine Structure and Lifetime of Dark Excitons in Transition Metal Dichalcogenide Monolayers
• Control of biaxial strain in single-layer Molybdenite using local thermal expansion of the substrate
• Dynamics and efficient conversion of excitons to trions in non-uniformly strained monolayer WS${}_2$
• Achieving Large, Tunable Strain in Monolayer Transition-Metal Dichalcogenides
• Phonon-assisted Photoluminescence from Dark Excitons in Monolayers of Transition Metal Dichalcogenides
• Strained bubbles in van der Waals heterostructures as local emitters of photoluminescence with adjustable wavelength
• Exciton diffusion in WSe2 monolayers embedded in a van der Waals heterostructure
• Exciton diffusion in monolayer semiconductors with suppressed disorder
• Exciton Relaxation Cascade in Two-dimensional Transition-metal dichalcogenides
• Exciton propagation and halo formation in two-dimensional materials
• Hybridized intervalley moiré excitons and flat bands in twisted WSe${}_2$ bilayers
• Impact of strain on the excitonic linewidth in transition metal dichalcogenides
• Intrinsic Lifetime of Higher Excitonic States in Tungsten Diselenide Monolayers
• Impact of strain on the optical fingerprint of monolayer transition metal dichalcogenides
• Quantum-dot-like states in molybdenum disulfide nanostructures due to the interplay of local surface wrinkling, strain, and dielectric confinement
• Negative excitonic diffusion in transition metal dichalcogenides
• Distinctive signatures of the spin- and momentum-forbidden dark exciton states in the photo-luminescences of strained WSe${}_2$ monolayers under thermalization
• Microscopic description of intraband absorption in graphene: the occurrence of transient negative differential transmission
• Strain dependence of photoluminescence and circular dichroism in transition metal dichalcogenides: a k.p analysis
• Indirect bandgap of hBN-encapsulated monolayer MoS2
• Brightening of spin- and momentum-dark excitons in transition metal dichalcogenides
• Temporal evolution of low-temperature phonon sidebands in WSe${}_2$ monolayers

Cited by in corpus (15)

• Exciton optics, dynamics and transport in atomically thin semiconductors
• Nonclassical Exciton Diffusion in Monolayer WSe2
• Exciton fine structure splitting and linearly polarized emission in strained transition-metal dichalcogenide monolayers
• 2D material exciton-polariton transport on 2D photonic crystals
• Spatiotemporal dynamics of free and bound excitons in CVD-grown MoS${}_2$ monolayer
• Single exciton trapping in an electrostatically defined 2D semiconductor quantum dot
• Photoluminescence kinetics of dark and bright excitons in atomically thin MoS${}_2$
• Two dimensional semiconductors: optical and electronic properties
• Probing the formation of dark interlayer excitons via ultrafast photocurrent
• Electron dynamics in a 2D nanobubble: A two-level system based on spatial density
• Topologically-enhanced exciton transport
• Polariton transport in 2D semiconductors: Phonon-mediated transitions between ballistic, superdiffusive and exciton-limited regimes
• Effects of Strain-Induced Pseudogauge Fields on Exciton Dispersion, Transport, and Interactions in Transition Metal Dichalcogenides Nanoribbons
• Trion-phonon interaction in atomically thin semiconductors
• Strain-induced exciton mobility in layered WS2 from first principles