Landau-quantized excitonic absorption and luminescence in a monolayer valley semiconductor

Abstract

We investigate Landau-quantized excitonic absorption and luminescence of monolayer WSe${}_2$ under magnetic field. We observe gate-dependent quantum oscillations in the bright exciton and trions (or exciton-polarons) as well as the dark trions and their phonon replicas. Our results reveal spin- and valley-polarized Landau levels (LLs) with filling factors $n=+0,+1$ in the bottom conduction band and $n=-0$ to $-6$ in the top valence band, including the Berry-curvature-induced $n=\pm 0$ LLs of massive Dirac fermions. The LL filling produces periodic plateaus in the exciton energy shift accompanied by sharp oscillations in the exciton absorption width and magnitude. This peculiar exciton behavior can be simulated by semi-empirical calculations. The experimentally deduced g-factors of the conduction band (g ~ 2.5) and valence band (g ~ 15) exceed those predicted in a single-particle model (g = 1.5, 5.5, respectively). Such g-factor enhancement implies strong many-body interactions in gated monolayer WSe${}_2$. The complex interplay between Landau quantization, excitonic effects, and many-body interactions makes monolayer WSe${}_2$ a promising platform to explore novel correlated quantum phenomena.

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Cited by in corpus (15)

• Multipath optical recombination of intervalley dark excitons and trions in monolayer WSe${}_2$
• Hexcitons and oxcitons in monolayer WSe${}_2$
• Spontaneous valley polarization of interacting carriers in a monolayer semiconductor
• Many-body exciton and inter-valley correlations in heavily electron-doped WSe${}_2$ monolayers
• Optical detection of long electron spin transport lengths in a monolayer semiconductor
• Excitons and trions in monolayer semiconductors with correlated electrons
• Anomalous magneto-optical response and chiral interface of dipolar excitons at twisted valleys
• Excitons in periodic potentials
• Ten-valley excitonic complexes in charge-tunable monolayer WSe${}_2$
• Excitons in Atomically Thin TMD in Electric and Magnetic Fields
• Landau-level composition of bound exciton states in magnetic field
• Energy shifts and broadening of excitonic resonances in electrostatically-doped semiconductors
• Signatures of valley drift in the diversified band dispersions of bright, gray, and dark excitons in MoS2 monolayers under uni-axial strains
• Two-dimensional bound excitons in real space and Landau quantization space: A comparative study
• Magnetoexcitons and Massive Dirac Fermions in Monolayers of Transition Metal Dichalcogenides in a High Magnetic Field