Bright and dark singlet excitons via linear and two-photon spectroscopy in monolayer transition-metal dichalcogenides

Abstract

We discuss the linear and two-photon spectroscopic selection rules for spin-singlet excitons in monolayer transition-metal dichalcogenides. Our microscopic formalism combines a fully $k$-dependent few-orbital band structure with a many-body Bethe-Salpeter equation treatment of the electron-hole interaction, using a model dielectric function. We show analytically and numerically that the single-particle, valley-dependent selection rules are preserved in the presence of excitonic effects. Furthermore, we definitively demonstrate that the bright (one-photon allowed) excitons have $s$-type azimuthal symmetry and that dark $p$-type excitons can be probed via two-photon spectroscopy. The screened Coulomb interaction in these materials substantially deviates from the $1/{\epsilon }_{0}r$ form; this breaks the "accidental" angular momentum degeneracy in the exciton spectrum, such that the 2$p$ exciton has a lower energy than the 2$s$ exciton by at least 50 meV. We compare our calculated two-photon absorption spectra to recent experimental measurements.

9 pages, 6 figures

References in corpus (11)

• The electronic properties of graphene
• Valley polarization in MoS2 monolayers by optical pumping
• Observation of giant bandgap renormalization and excitonic effects in a monolayer transition metal dichalcogenide semiconductor
• Measurement of the optical dielectric function of transition metal dichalcogenide monolayers: MoS2, MoSe2, WS2 and WSe2
• Tightly bound excitons in monolayer WSe2
• Probing Excitonic Dark States in Single-layer Tungsten Disulfide
• Non-linear Optical Spectroscopy of Excited Exciton States for Efficient Valley Coherence Generation in WSe2 Monolayers
• Exciton band structure of monolayer MoS2
• Chirality and Correlations in Graphene
• Anisotropic exciton Stark shift in black phosphorus
• Signatures of Bloch-band geometry on excitons: non-hydrogenic spectra in transition metal dichalcogenides

Cited by in corpus (42)

• Excitons in atomically thin transition metal dichalcogenides
• Exciton Diamagnetic Shifts and Valley Zeeman Effects in Monolayer WS${}_2$ and MoS${}_2$ to 65 Tesla
• Dark excitons in transition metal dichalcogenides
• Enabling valley selective exciton scattering in monolayer WSe${}_2$ through upconversion
• Magnetic Proximity Effects in Transition-Metal Dichalcogenides: Converting Excitons
• Berry phase modification to the energy spectrum of excitons
• Environmentally-Sensitive Theory of Electronic and Optical Transitions in Atomically-Thin Semiconductors
• Binding energies and spatial structures of small carrier complexes in monolayer transition metal dichalcogenides via diffusion Monte Carlo
• Excitons in boron nitride single layer
• High-temperature superfuidity of the two-component Bose gas in a TMDC bilayer
• Band Topology, Orbital Phase Winding, and Selection Rules in Excitonic Physics in Two Dimensions
• Intrinsic exciton states mixing and non-linear optical properties in transition metal dichalcogenide monolayers
• Magneto-photoluminescence of exciton Rydberg states in monolayer WSe${}_2$
• Probing Many-Body Interactions in Monolayer Transition-Metal Dichalcogenides
• Excitonic Stark effect in MoS${}_2$ monolayers
• Mapping of the dark exciton landscape in transition metal dichalcogenides
• Many-Body Simulation of Two-Dimensional Electronic Spectroscopy of Excitons and Trions in Monolayer Transition-Metal Dichalcogenides
• Excitonic effects in the optical properties of 2D materials: An equation of motion approach
• Valley-dependent Exciton Fine Structure and Autler-Townes Doublets from Berry Phases in Monolayer Molybdenum Diselenide
• Distinctive signatures of the spin- and momentum-forbidden dark exciton states in the photo-luminescences of strained WSe${}_2$ monolayers under thermalization
• Optical Absorption by Dirac Excitons in Single-Layer Transition-Metal Dichalcogenides
• Model Prediction of Self-Rotating Excitons in Two-Dimensional Transition-Metal Dichalcogenides
• Optically Probing Tunable Band Topology in Atomic Monolayers
• Two-photon absorption in two-dimensional materials: The case of hexagonal boron nitride
• Fundamental exciton linewidth broadening in monolayer transition metal dichalcogenides
• Strong Single- and Two-Photon Luminescence Enhancement by Nonradiative Energy Transfer across Layered Heterostructure
• Band nesting and exciton spectrum in monolayer MoS${}_2$
• Optical fingerprint of dark 2p-states in transition metal dichalcogenides
• Valley polarization control in WSe2 monolayer by a single-cycle laser pulse
• Microscopic theory of cavity-confined monolayer semiconductors: polariton-induced valley relaxation and the prospect of enhancing and controlling the valley pseudospin by chiral strong coupling
• Light-matter coupling and non-equilibrium dynamics of exchange-split trions in monolayer WS2
• Emergent bright excitons with Rashba spin-orbit coupling in atomic monolayers
• Anisotropic exciton transport in transition-metal dichalcogenides
• Pump-triple sum-frequency-probe spectroscopy of transition metal dichalcogenides
• Subcycle control of valley-selective excitation via dynamical Franz-Keldysh effect in WSe${}_2$ monolayer
• Two-dimensional excitons from twisted light and the fate of the photon's orbital angular momentum
• Intrinsic edge excitons in two-dimensional MoS${}_2$
• Attosecond All-Optical Retrieval of Valley Polarization via Circular Dichroism in Transient Absorption
• Excitonic effect on two-photon absorption of two-dimensional semiconductors: Theory and applications to MoS2 and WS2 monolayers
• Mixed quantum-classical modeling of exciton-phonon scattering in solids: Application to optical linewidths of monolayer MoS2
• Tunable resonant s-p mixing of excitons in van der Waals heterostructures
• Nonlinear optics in the electron-hole continuum in 2D semiconductors: two-photon transition, second harmonic generation and valley current injection