Spin-momentum locked interaction between guided photons and surface electrons in topological insulators

Siyuan Luo, Li He, Mo Li

Research output: Contribution to journalArticlepeer-review

24 Scopus citations


The propagation of electrons and photons can respectively have the spin-momentum locking effect which correlates spin with linear momentum. For surface electrons in three-dimensional topological insulators (TIs), their spin is locked to the transport direction. Analogously, photons in optical waveguides carry transverse spin angular momentum which is also locked to the propagation direction. A direct connection between electron and photon spins occurs in TIs due to spin-dependent selection rules of optical transitions. Here we demonstrate an optoelectronic device that integrates a TI with a photonic waveguide. Interaction between photons in the waveguide and surface electrons in a Bi2Se3 layer generates a directional, spin-polarized photocurrent. Because of spin-momentum locking, changing light propagation direction reverses photon spin and thus the direction of the photocurrent. Our device represents a way of implementing coupled spin-orbit interaction between electrons and photons and may lead to applications in opto-spintronics and quantum information processing.

Original languageEnglish (US)
Article number2141
JournalNature communications
Issue number1
StatePublished - Dec 1 2017

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© 2017 The Author(s).


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