Valley Plasmonics in the Dichalcogenides

Abstract

The rich phenomenology of plasmonic excitations in the dichalcogenides is analyzed as a function of doping. The many-body polarization, the dielectric response function and electron energy loss spectra are calculated using an ab initio based model involving material-realistic Coulomb interactions, band structure and spin-orbit coupling. Focusing on the representative case of MoS${}_2$, a plethora of plasmon bands are observed, originating from scattering processes within and between the conduction or valence band valleys. We discuss the resulting square-root and linear collective modes, arising from long-range versus short-range screening of the Coulomb potential. We show that the multi-orbital nature of the bands and spin-orbit coupling strongly affects inter-valley scattering processes by gapping certain two-particle modes at large momentum transfer.

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• Real-time GW: Toward an ab initio description of the ultrafast carrier and exciton dynamics in two-dimensional materials
• Dynamical screening in monolayer transition-metal dichalcogenides and its manifestations in the exciton spectrum
• Competing Coulomb and electron-phonon interactions in NbS${}_2$
• Excitation-induced transition to indirect band gaps in atomically thin transition metal dichalcogenide semiconductors
• Anisotropic features in the electronic structure of the two-dimensional transition metal trichalcogenide TiS${}_3$: electron doping and plasmons
• Plasmonic physics of 2D crystalline materials
• Gapped collective charge excitations and interlayer hopping in cuprate superconductors
• Frequency-dependent substrate screening of excitons in atomically thin transition metal dichalcogenide semiconductors
• Flat-band plasmons in twisted bilayer transition metal dichalcogenides
• Interplay of screening and superconductivity in low-dimensional materials
• Ab initio study of electromagnatic modes in two-dimensional semiconductors: Application to doped phosphorene
• Theory of coherent phonons coupled to excitons
• Plasmon modes of bilayer molybdenum disulfide: A density functional study
• Ultrafast creation and melting of nonequilibrium excitonic condensates in bulk WSe${}_2$
• Effects of Structural Distortions on the Electronic Structure of T-type Transition Metal Dichalcogenides
• Plasmonic Waveguides from Coulomb-Engineered Two-Dimensional Metals
• Quantum beats of coherent 1s 2s excitons in two dimensional transition metal