Optical Selection Rule based on Valley-Exciton Locking for 2D Valleytronics
arXiv:1504.04947 · doi:10.1038/lsa.2015.139
Abstract
Optical selection rule fundamentally determines the optical transition between energy states in a variety of physical systems from hydrogen atoms to bulk crystals such as GaAs. It is important for optoelectronic applications such as lasers, energy-dispersive X-ray spectroscopy and quantum computation. Recently, single layer transition metal dichalcogenide (TMDC) exhibits valleys in momentum space with nontrivial Berry curvature and excitons with large binding energy. However, it is unclear how the unique valley degree of freedom combined with the strong excitonic effect influences the optical excitation. Here we discover a new set of optical selection rules in monolayer WS2,imposed by valley and exciton angular momentum. We experimentally demonstrated such a principle for second harmonic generation (SHG) and two-photon luminescence (TPL). Moreover, the two-photon induced valley populations yield net circular polarized photoluminescence after a sub-ps interexciton relaxation (2p->1s) and last for 8 ps. The discovery of this new optical selection rule in valleytronic 2D system not only largely extend information degrees but sets a foundation in control of optical transitions that is crucial to valley optoeletronic device applications such as 2D valley-polarized light emitting diodes (LED), optical switches and coherent control for quantum computing.
References in corpus (10)
- Valley polarization in MoS2 monolayers by optical pumping
- Ultrafast Charge Transfer in Atomically Thin MoS2/WS2 Heterostructures
- The Valley Hall Effect in MoS2 Transistors
- Tightly bound excitons in monolayer WSe2
- Valley Dependent Optoelectronics from Inversion Symmetry Breaking
- Probing Excitonic Dark States in Single-layer Tungsten Disulfide
- Exciton Binding Energy of Monolayer WS2
- Electronic structures and theoretical modelling of two-dimensional group-VIB transition metal dichalcogenides
- Non-linear Optical Spectroscopy of Excited Exciton States for Efficient Valley Coherence Generation in WSe2 Monolayers
- Electrical Control of Second-Harmonic Generation in a WSe2 Monolayer Transistor
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- Routing of valley photons in a WS2 monolayer via delocalized Bloch modes of in-plane inversion-symmetry broken photonic crystal slabs
- Excitonic properties of semiconducting monolayer and bilayer MoTe2
- Band Topology, Orbital Phase Winding, and Selection Rules in Excitonic Physics in Two Dimensions
- Nonlinear optical selection rules of excitons in monolayer transition metal dichalcogenides
- Two-photon absorption in two-dimensional materials: The case of hexagonal boron nitride
- Second-harmonic imaging of plasmonic Pancharatnam-Berry phase metasurfaces coupled to monolayers of WS2
- Influence of plasmon resonances and symmetry effects on second harmonic generation in WS2-plasmonic hybrid metasurfaces
- Optical nonlinearities of excitons in monolayer MoS2
- Engineering photonic environments for two-dimensional materials
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- Probing Electronic States in Monolayer Semiconductors through Static and Transient Third-Harmonic Spectroscopy
- Creation and control of valley currents in graphene by few cycle light pulses
- Valley Emission and Upconversion in Isotopically Engineered Monolayer WS under Resonant Excitation
- Ultrafast Saddletronics