Newly observed first-order resonant Raman modes in few-layer MoS${}_2$

Abstract

We report two new first-order Raman modes in the spectra of few-layer MoS${}_2$ at 286~cm${}^{-1}$ and 471~cm${}^{-1}$ for excitation energies above 2.4~eV. These modes appear only in few-layer MoS${}_2$; therefore their absence provides an easy and accurate method to identify single-layer MoS${}_2$. We show that these modes are related to phonons that are not observed in the single layer due to their symmetry. Each of these phonons leads to several nearly degenerate phonons in few-layer samples. The nearly degenerate phonons in few-layer materials belong to two different symmetry representations, showing opposite behavior under inversion or horizontal reflection. As a result, Raman active phonons exist in few-layer materials that have nearly the same frequency as the symmetry forbidden phonon of the single layer. We provide here a general treatment of this effect for all few-layer two-dimensional crystal structures with an inversion center or a mirror plane parallel to the layers. We show that always nearly degenerate phonon modes of different symmetry must occur and, as a result, similar pseudo-activation effects can be excepted.

References in corpus (26)

• Atomically thin MoS2: A new direct-gap semiconductor
• Van der Waals heterostructures
• Anomalous Lattice Vibrations of Single and Few-Layer MoS2
• Bandgap Engineering of Strained Monolayer and Bilayer MoS2
• Pseudopotentials for high-throughput DFT calculations
• Phonons in single and few-layer MoS2 and WS2
• Symmetry-dependent phonon renormalization in monolayer MoS2 transistor
• Experimental demonstration of continuous electronic structure tuning via strain in atomically thin MoS2
• The Shear Mode of Multi-Layer Graphene
• Interlayer breathing and shear modes in few-trilayer MoS2 and WSe2
• Large and tunable photo-thermoelectric effect in single-layer MoS2
• Shear and Layer Breathing Modes in Multilayer MoS2
• Effect of spin-orbit interaction on the excitonic effects in single-layer, double-layer, and bulk MoS2
• Photoluminescence of freestanding single- and few-layer MoS2
• Analytical approach to excitonic properties of MoS2
• Raman spectroscopy of the interlayer shear mode in few-layer MoS2 flakes
• Crystal Symmetry Breaking in Few-Quintuple Bismuth Telluride Films: Applications in Nanometrology of Topological Insulators
• Group theory analysis of electrons and phonons in N-layer graphene systems
• Low-Frequency Raman Modes and Electronic Excitations In Atomically Thin MoS2 Crystals
• Probing the Role of Interlayer Coupling and Coulomb Interactions on Electronic Structure in Few-Layer MoSe2 Nanostructures
• Anomalous excitonic resonance Raman effects in few-layer MoS2
• Layer breathing modes in few-layer graphene
• Vibrational properties of graphene nanoribbons by first-principles calculations
• Splitting of the monolayer out-of-plane A'1 Raman mode in few-layer WS2
• Phonon and Thermal Properties of Exfoliated Tantalum Diselenide Thin Films
• Layer number determination in graphene using out-of-plane vibrations

Cited by in corpus (36)

• Excitons in atomically thin transition metal dichalcogenides
• Fingerprints of the Strong Interaction between Monolayer MoS2 and Gold
• Splitting of interlayer shear modes and photon energy dependent anisotropic Raman response in $N$-layer ReSe${}_2$ and ReS${}_2$
• Chemical Vapor Deposition Synthesized Atomically Thin Molybdenum Disulfide with Optoelectronic-Grade Crystalline Quality
• Resonance effects in the Raman scattering of mono- and few layers MoSe${}_2$
• Mapping of Low-Frequency Raman Modes in CVD-Grown Transition Metal Dichalcogenides: Layer Number, Stacking Orientation and Resonant Effects
• Unified description of the optical phonon modes in $N$-layer MoTe${}_2$
• Raman Signatures of Polytypism in Molybdenum Disulfide
• Light matter interaction in transition metal dichalcogenides and their heterostructures
• Workhorse minimally-empirical dispersion-corrected density functional, with tests for weakly-bound systems: r${}^2$SCAN+rVV10
• Guide to optical spectroscopy of layered semiconductors
• Strongly coupled coherent phonons in single-layer MoS${}_2$
• Phonon dispersion of MoS${}_2$
• A library of ab initio Raman spectra for automated identification of 2D materials
• Light-Matter Interactions in Two-Dimensional Transition Metal Dichalcogenides: Dominant Excitonic Transitions in mono- and few-layer MoX${}_2$ and Band Nesting
• Observation of forbidden phonons and dark excitons by resonance Raman scattering in few-layer WS${}_2$
• Quantum interference effects in resonant Raman spectroscopy of single- and triple-layer MoTe${}_2$ from first principles
• Shear and breathing modes of layered materials
• Resonance profiles of valley polarization in single-layer MoS${}_2$ and MoSe${}_2$
• Resonant Raman and photoluminescence spectra of suspended molybdenum disulfide
• Electron-phonon and phonon-phonon anharmonic interactions in 2H-MoX2 (X=S, Te): A comprehensive Resonant Raman study
• Macroscopic Single-Phase Monolayer Borophene on Arbitrary Substrates
• Thermal Expansion Coefficient and Phonon Dynamics in Coexisting Allotropes of Monolayer WS2 Probed by Raman Scattering
• Low wavenumber Raman spectroscopy of highly crystalline MoSe2 grown by chemical vapor deposition
• Temperature induced modulation of resonant Raman scattering in bilayer 2H-MoS${}_2$
• Breakdown of Raman Selection Rules By Fröhlich Interaction in Few-Layer WS${}_2$
• Rigid-layer Raman-active modes in $N$-layer Transition Metal Dichalcogenides: interlayer force constants and hyperspectral Raman imaging
• Davydov Splitting, Resonance Effect and Phonon Dynamics in CVD grown Layered MoS2
• Raman scattering from the bulk inactive out-of-plane B${}_{2\text{g}}^1$ mode in few-layer MoTe${}_2$
• Vibrational and dielectric properties of monolayer transition metal dichalcogenides
• Interlayer excitonic spectra of vertically stacked MoSe${}_2$/WSe${}_2$ heterobilayers
• Ultrafast charge dynamics and photoluminescence in bilayer MoS2
• Interlayer Raman modes in twisted bilayer TMDCs
• Surface Sensitive Raman Response of Metal-Supported Monolayer MoS${}_2$
• Symmetries in zero and finite center-of-mass momenta excitons
• Raman scattering and anomalous Stokes anti-Stokes ratio in MoTe2 atomic layers