Stacking-dependent exciton multiplicity in WSe${}_2$ bilayers

Abstract

Twisted layers of atomically thin two-dimensional materials realize a broad range of novel quantum materials with engineered optical and transport phenomena arising from spin and valley degrees of freedom and strong electron correlations in hybridized interlayer bands. Here, we report experimental and theoretical studies of WSe${}_2$ homobilayers obtained in two stable configurations of 2H ($60^{\circ }$ twist) and 3R ($0^{\circ }$ twist) stackings by controlled chemical vapor synthesis of high-quality large-area crystals. Using optical absorption and photoluminescence spectroscopy at cryogenic temperatures, we uncover marked differences in the optical characteristics of 2H and 3R bilayer WSe${}_2$ which we explain on the basis of beyond-DFT theoretical calculations. Our results highlight the role of layer stacking for the spectral multiplicity of momentum-direct intralayer exciton transitions in absorption, and relate the multiplicity of phonon sidebands in the photoluminescence to momentum-indirect excitons with different spin valley and layer character. Our comprehensive study generalizes to other layered homobilayer and heterobilayer semiconductor systems and highlights the role of crystal symmetry and stacking for interlayer hybrid states.

References in corpus (59)

• Atomically thin MoS2: A new direct-gap semiconductor
• Wannier90: A Tool for Obtaining Maximally-Localised Wannier Functions
• Excitons in atomically thin transition metal dichalcogenides
• Optical signature of symmetry variations and spin-valley coupling in atomically thin tungsten dichalcogenides
• Magic continuum in twisted bilayer WSe2
• Magnetic Control of Valley Pseudospin in Monolayer WSe2
• Stacking-engineered ferroelectricity in bilayer boron nitride
• Lattice dynamics in mono- and few-layer sheets of WS2 and WSe2
• Valley Zeeman Effect in Elementary Optical Excitations of a Monolayer WSe2
• Interfacial Ferroelectricity by van-der-Waals Sliding
• Evolution of Interlayer Coupling in Twisted MoS2 Bilayers
• The hot pick-up technique for batch assembly of van der Waals heterostructures
• Excitonic linewidth approaching the homogeneous limit in MoS2 based van der Waals heterostructures : accessing spin-valley dynamics
• Anomalous Raman Spectra and Thickness Dependent Electronic properties of WSe2
• Origin of indirect optical transitions in few-layer MoS2, WS2 and WSe2
• Cleaning Interfaces in Layered Materials Heterostructures
• Halide-Assisted Atmospheric Pressure Growth of Large WSe2 and WS2 Monolayer Crystals
• Atomic reconstruction in twisted bilayers of transition metal dichalcogenides
• Electronic and Thermoelectric Properties of Few-Layer Transition Metal Dichalcogenides
• Magnetoelectric effects and valley controlled spin quantum gates in transition metal dichalcogenide bilayers
• Interfacial ferroelectricity in marginally twisted 2D semiconductors
• Charge-polarized interfacial superlattices in marginally twisted hexagonal boron nitride
• Relaxation and Domain Formation in Incommensurate 2D Heterostructures
• Charge-tuneable biexciton complexes in monolayer WSe${}_2$
• Revealing the Biexciton and Trion-exciton Complexes in BN Encapsulated WSe2
• Stacking domains and dislocation networks in marginally twisted bilayers of transition metal dichalcogenides
• Broken mirror symmetry in excitonic response of reconstructed domains in twisted MoSe${}_2$/MoSe${}_2$ bilayers
• Moiré Excitons Correlated with Superlattice Structure in Twisted WSe${}_2$/WSe${}_2$ Homobilayers
• Indirect excitons in van der Waals heterostructures at room temperature
• Chemical Vapor Deposition Synthesized Atomically Thin Molybdenum Disulfide with Optoelectronic-Grade Crystalline Quality
• Direct exciton emission from atomically thin transition metal dichalcogenide heterostructures near the lifetime limit
• Electrical tuning of layer-polarized exciton gases in WSe2 bilayers
• Electrically tunable valley dynamics in twisted WSe${}_2$/WSe${}_2$ bilayers
• Magneto-optics in transition metal diselenide monolayers
• Interlayer excitons in bilayer MoS2 with strong oscillator strength up to room temperature
• Biexciton fine structure in monolayer transition metal dichalcogenides
• Spontaneous Polarization Induced Photovoltaic Effect In Rhombohedrally Stacked MoS${}_2$
• Optical response of monolayer, few-layer and bulk tungsten disulfide
• Giant Stark splitting of an exciton in bilayer MoS${}_2$
• Exciton g-factors of van der Waals heterostructures from first principles calculations
• Controlling interlayer excitons in MoS2 layers grown by chemical vapor deposition
• Accessing high optical quality of MoS2 monolayers grown by chemical vapor deposition
• The role of momentum-dark excitons in the elementary optical response of bilayer WSe${}_2$
• Guide to optical spectroscopy of layered semiconductors
• Moiré excitons in MoSe${}_2$-WSe${}_2$ heterobilayers and heterotrilayers
• Ab-initio studies of exciton $g$ factors: Monolayer transition metal dichalcogenides in magnetic fields
• Exciton g-factors in monolayer and bilayer WSe${}_2$ from experiment and theory
• Hybridized intervalley moiré excitons and flat bands in twisted WSe${}_2$ bilayers
• Observation of Inter-layer Excitons in MoSe2 Single Crystals
• Dipolar and magnetic properties of strongly absorbing hybrid interlayer excitons in pristine bilayer MoS${}_2$
• Twist-angle engineering of excitonic quantum interference and optical nonlinearities in stacked 2D semiconductors
• Valley Zeeman effect and Landau levels in Two-Dimensional Transition Metal Dichalcogenides
• Multifaceted moiré superlattice physics in twisted WSe${}_2$ bilayers
• Dependence of the hBN Layer Thickness on the Band Structure and Exciton Properties of Encapsulated WSe2 Monolayers
• Fine structure of $\mathrm{K}$-excitons in multilayers of transition metal dichalcogenides
• Weak ferroelectric charge transfer in layer-asymmetric bilayers of 2D semiconductors
• Stacking-Dependent Optical Properties in Bilayer WSe2
• Spatially indirect intervalley excitons in bilayer WSe2
• Electric-field-tunable intervalley excitons and phonon replicas in bilayer WSe${}_2$

Cited by in corpus (7)

• Reconfigurable Multifunctional van der Waals Ferroelectric Devices and Logic Circuits
• Excitonic signatures of ferroelectric order in parallel-stacked MoS${}_2$
• Electrically tunable dipolar interactions between layer-hybridized excitons
• Robust Zeeman-type band splitting in sliding ferroelectrics
• Electrically tunable and enhanced nonlinearity of moiré exciton-polaritons in transition metal dichalcogenide bilayers
• Robust Interlayer Exciton Interplay in Twisted van der Waals Heterotrilayer on a Broadband Bragg Reflector up to Room Temperature
• Moire-Engineered Excitonic Landscape and Phonon-Mediated Recombination in Twisted WSe2 Bilayers