Control of valley-polarized exciton currents in 2D heterostructures
ORAL
Abstract
Valleytronics is an alternative to charge-based electronics aiming at encoding data in the valley degree of freedom, which could enable new paradigms for computing devices. Transition metal dichalcogenides (TMDCs) are an ideal platform for this due to the combination of unique spin–valley physics and direct bandgap, allowing optical initialization and readout of the valley state. Recent developments in the control of interlayer excitons in heterostructures of these materials offer an effective way to realize valley-optoelectronic devices [1]. Here, we show the generation and transport over mesoscopic distances of valley-polarized excitons in a device based on a type-II TMDC heterostructure. Engineering of the interlayer coupling results in enhanced diffusion of valley-polarized excitons, which can be controlled and switched electrically [2]. Furthermore, using electrostatic traps we can increase the exciton concentration by an order of magnitude, reaching densities higher than 1012 cm-2, a promising approach to obtain coherent quantum states of excitons.
[1] Ciarrocchi*, Unuchek* et al. Nat. Photon., 13, 2, (2019)
[2] Unuchek*, Ciarrocchi* et al. Nat. Nanotechnol. (2019)
[1] Ciarrocchi*, Unuchek* et al. Nat. Photon., 13, 2, (2019)
[2] Unuchek*, Ciarrocchi* et al. Nat. Nanotechnol. (2019)
*Swiss National Science Foundation, H2020 European Research Council and Marie Curie-Sklodowska-Curie Action
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Presenters
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Alberto Ciarrocchi
- Ecole Polytechnique Federale de Lausanne