Hybrid dark excitons in monolayer MoS2

  title={Hybrid dark excitons in monolayer 
  author={Hong Liu and A. A. Pau and Dmitry K. Efimkin},
  journal={Physical Review B},
Transition metal dichalcogenides have a rich exciton landscape consisting of a variety of bright and dark excitonic states. We consider the lowest-energy dark states in MoS2, which can be referred to as hybrid excitons, as they are formed by a Dirac electron and a Schrödinger hole. The chiral nature of the Dirac electron introduces asymmetry to the excited exciton state spectrum and couples the relative motion of the electron and hole with the center-of-mass motion. We demonstrate that this… 

Figures and Tables from this paper


Dark excitons in transition metal dichalcogenides
Monolayer transition metal dichalcogenides (TMDs) exhibit a remarkably strong Coulomb interaction that manifests in tightly bound excitons. Due to the complex electronic band structure exhibiting
Magnetic brightening and control of dark excitons in monolayer WSe2.
It is shown how an in-plane magnetic field can brighten the dark excitons in monolayer WSe2 and permit their properties to be observed experimentally and the fine spin-splitting at the conduction band edges is revealed.
Momentum-Dark Intervalley Exciton in Monolayer Tungsten Diselenide Brightened via Chiral Phonon.
This work reports the unambiguous identification of the momentum-dark, intervalley exciton in monolayer WSe2 through low-temperature magneto-photoluminescence (PL) spectra and adds an exciting quasiparticle for valleytronics.
Exciton Relaxation Cascade in two-dimensional Transition Metal Dichalcogenides
A fully quantum mechanical description of momentum- and energy-resolved exciton dynamics in monolayer molybdenum diselenide (MoSe2) including optical excitation, formation of excitons, radiative recombination as well as phonon-induced cascade-like relaxation down to the excitonic ground state is provided.
Exciton Hall effect in monolayer MoS2.
The present result not only poses a fundamental problem of the Hall effect in composite particles, but also offers a route to explore exciton-based valleytronics in two-dimensional materials.
Mapping of the dark exciton landscape in transition metal dichalcogenides
Transition metal dichalcogenides (TMDs) exhibit a remarkable exciton physics including bright and optically forbidden dark excitonic states. Here, we show how dark excitons can be experimentally
Dirac cones and Dirac saddle points of bright excitons in monolayer transition metal dichalcogenides.
The strain-tunable valley-orbit coupling implies new structures of exciton condensates, new functionalities of excitonic circuits and mechanical control of valley pseudospin, which point to unique opportunities to study Dirac physics.
Valley-selective chiral phonon replicas of dark excitons and trions in monolayer WSe2
We observe a set of three replica luminescent peaks at ~21.4 meV below the dark exciton, negative and positive dark trions (or exciton-polarons) in monolayer WSe2. The replica redshift energy matches
Probing dark excitons in atomically thin semiconductors via near-field coupling to surface plasmon polaritons.
The SPP-based near-field spectroscopy significantly improves experimental capabilities for probing and manipulating exciton dynamics of atomically thin materials, thus opening up new avenues for realizing active metasurfaces and robust optoelectronic systems, with potential applications in information processing and communication.
Robust room temperature valley Hall effect of interlayer excitons.
The demonstration of the robust interlayer exciton VHE at room temperature, enabled by their intrinsically long lifetimes, will open up realistic possibilities for the development of opto-valleytronic devices based on TMD heterostructures.