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

14 Scopus citations

Abstract

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
Volume8
Issue number1
DOIs
StatePublished - Dec 1 2017

Bibliographical note

Funding Information:
This work was supported by C-SPIN, one of the six centers of STARnet, a Semiconductor Research Corporation program, sponsored by MARCO and DARPA, and the National Science Foundation (Award No. ECCS-1351002). L.H. acknowledges the support of Doctoral Dissertation Fellowship provided by the Graduate School of the University of Minnesota. S.L. acknowledges the scholarship provided by the China Scholarship Council. Parts of this work were carried out in the University of Minnesota Nanofabrication Center which receives partial support from NSF through NNCI program, and the Characterization Facility which is a member of the NSF-funded Materials Research Facilities Network via the MRSEC program.

Funding Information:
This work was supported by C-SPIN, one of the six centers of STARnet, a Semiconductor Research Corporation program, sponsored by MARCO and DARPA, and the National Science Foundation (Award No. ECCS-1351002). L.H. acknowledges the support of Doctoral Dissertation Fellowship provided by the Graduate School of the University of Minnesota. S.L. acknowledges the scholarship provided by the China Scholarship Council. Parts of this work were carried out in the University of Minnesota Nanofab-rication Center which receives partial support from NSF through NNCI program, and the Characterization Facility which is a member of the NSF-funded Materials Research Facilities Network via the MRSEC program.

Publisher Copyright:
© 2017 The Author(s).

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