Many-body exciton and inter-valley correlations in heavily electron-doped WSe${}_2$ monolayers

Abstract

In monolayer transition-metal dichalcogenide semiconductors, many-body correlations can manifest in optical spectra when photoexcited electron-hole pairs (excitons) are introduced into a 2D Fermi sea of mobile carriers. At low carrier densities, the formation of positively and negatively charged excitons ($X^{\pm }$) is well documented. However, in WSe${}_2$ monolayers, an additional absorption resonance, often called $X^{-\prime }$, emerges at high electron density. Its origin is not understood. Here we investigate the $X^{-\prime }$ state via polarized absorption spectroscopy of electrostatically-gated WSe${}_2$ monolayers in high magnetic fields to 60~T. Field-induced filling and emptying of the lowest optically-active Landau level in the $K^{\prime }$ valley causes repeated quenching of the corresponding optical absorption. Surprisingly, however, these quenchings are accompanied by absorption changes to higher-lying Landau levels in both $K^{\prime }$ and $K$ valleys, which are unoccupied. These results cannot be reconciled within a single-particle picture, and demonstrate the many-body nature and inter-valley correlations of the $X^{-\prime }$ quasiparticle state.

3 figures, 7 pages, in press at Nano Letters

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Cited by in corpus (14)

• Exciton optics, dynamics and transport in atomically thin semiconductors
• Hexcitons and oxcitons in monolayer WSe${}_2$
• Quantum Dynamics of Attractive and Repulsive Polarons in a Doped MoSe${}_2$ Monolayer
• Composite excitonic states in doped semiconductors
• Emergence of 6-particle "hexciton'' states in WS${}_2$ and MoSe${}_2$ monolayers
• Excitons and trions in monolayer semiconductors with correlated electrons
• Interplay of valley polarized dark trion and dark exciton-polaron in monolayer WSe2
• Ten-valley excitonic complexes in charge-tunable monolayer WSe${}_2$
• Efficient calculation of trion energies in monolayer transition metal dichalcogenides
• Excitons in periodic potentials
• Landau-level composition of bound exciton states in magnetic field
• Energy shifts and broadening of excitonic resonances in electrostatically-doped semiconductors
• Optical response of WSe${}_2$-based vertical tunneling junction
• Two-dimensional bound excitons in real space and Landau quantization space: A comparative study