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Imaging of pure spin-valley diffusion current in WS2-WSe2 heterostructures

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Science  25 May 2018:
Vol. 360, Issue 6391, pp. 893-896
DOI: 10.1126/science.aao3503

Tracking the spin-valley current

Taking advantage of the electron's spin and valley degrees of freedom requires a method for generating currents of carriers that have a particular spin or come from a particular valley in the electronic structure. Jin et al. used a heterostructure made out of adjacent layers of WSe2 and WS2 to create a spin-valley diffusion current without applying an external electric field. Instead, they used circularly polarized laser light to initiate the diffusion and a second laser pulse to image the propagation of the carriers. With long lifetimes and diffusion lengths, the method may be of practical use in future valleytronic devices.

Science, this issue p. 893