Optically bright $p$-excitons indicating strong Coulomb coupling in transition-metal dichalcogenides

Abstract

It is shown that the strong Coulomb coupling in intrinsic suspended semiconducting transition metal dichalcogenides can exceed the critical value needed for an excitonic ground state. The dipole-allowed optical excitations then correspond to intra-excitonic transitions such that the optically bright excitonic transitions near the Dirac points have a $p$-like symmetry whereas the $s$-like states are dipole forbidden. The large intrinsic coupling strength seems to be a generic property of the semiconducting transition metal dichalcogenides and strong Coulomb-coupling signatures in the form of the optical selection rules can be observed even in samples grown on typical substrates like SiO${}_2$. For the examples of WS${}_2$ and WSe${}_2$, excellent agreement of the computed excitonic resonance energies with recent experiments is demonstrated.

Accepted for publication on Journal of Physics C: Condensed Matter

References in corpus (8)

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• Exciton Binding Energy and Nonhydrogenic Rydberg Series in Monolayer WS2
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Cited by in corpus (15)

• Excitons in atomically thin transition metal dichalcogenides
• Exciton Diamagnetic Shifts and Valley Zeeman Effects in Monolayer WS${}_2$ and MoS${}_2$ to 65 Tesla
• Magneto-Optics of Exciton Rydberg States in a Monolayer Semiconductor
• Berry phase modification to the energy spectrum of excitons
• Intrinsic exciton states mixing and non-linear optical properties in transition metal dichalcogenide monolayers
• Excitonic Stark effect in MoS${}_2$ monolayers
• Influence of the effective layer thickness on the groundstate and excitonic properties of transition-metal dichalcogenide systems
• Optical Absorption by Dirac Excitons in Single-Layer Transition-Metal Dichalcogenides
• Model Prediction of Self-Rotating Excitons in Two-Dimensional Transition-Metal Dichalcogenides
• On the Optical Properties of Excitons in Buckled 2D Materials in an External Electric Field
• Optical selection rules for excitonic Rydberg series in the massive Dirac cones of hexagonal 2D materials
• Effect of intravalley and intervalley electron-hole exchange on the nonlinear optical response of monolayer MoSe${}_2$
• Magneto-reflection spectroscopy of monolayer transition-metal dichalcogenide semiconductors in pulsed magnetic fields
• Coulomb effects in the absorbance spectra of two-dimensional Dirac materials
• Long-lived Nonlinear Oscillatory States in Interacting Relativistic Bose-Einstein Condensates