Imaging of pure spin-valley diffusion current in WS<sub>2</sub>-WSe<sub>2</sub> heterostructures.
basic_science · Level V
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- Record sourced from PubMed, PMID 29798880.
- Also identified by DOI 10.1126/science.aao3503.
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Abstract
Transition metal dichalcogenide (TMDC) materials are promising for spintronic and valleytronic applications because valley-polarized excitations can be generated and manipulated with circularly polarized photons and the valley and spin degrees of freedom are locked by strong spin-orbital interactions. In this study we demonstrate efficient generation of a pure and locked spin-valley diffusion current in tungsten disulfide (WS<sub>2</sub>)-tungsten diselenide (WSe<sub>2</sub>) heterostructures without any driving electric field. We imaged the propagation of valley current in real time and space by pump-probe spectroscopy. The valley current in the heterostructures can live for more than 20 microseconds and propagate over 20 micrometers; both the lifetime and the diffusion length can be controlled through electrostatic gating. The high-efficiency and electric-field-free generation of a locked spin-valley current in TMDC heterostructures holds promise for applications in spin and valley devices.