Manipulating spin-polarized photocurrents in 2D transition metal dichalcogenides.

Xie, Lu; Cui, Xiaodong · Proc Natl Acad Sci U S A · 2016

basic_science · Level V

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Abstract

Manipulating spin polarization of electrons in nonmagnetic semiconductors by means of electric fields or optical fields is an essential theme of the conceptual nonmagnetic semiconductor-based spintronics. Here we experimentally demonstrate an electric method of detecting spin polarization in monolayer transition metal dichalcogenides (TMDs) generated by circularly polarized optical pumping. The spin-polarized photocurrent is achieved through the valley-dependent optical selection rules and the spin-valley locking in monolayer WS2, and electrically detected by a lateral spin-valve structure with ferromagnetic contacts. The demonstrated long spin-valley lifetime, the unique valley-contrasted physics, and the spin-valley locking make monolayer WS2 an unprecedented candidate for semiconductor-based spintronics.