Control over topological insulator photocurrents with light polarization

J. W. McIver, D. Hsieh, H. Steinberg, P. Jarillo-Herrero, N. Gedik*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

511 Scopus citations

Abstract

Three-dimensional topological insulators represent a new quantum phase of matter with spin-polarized surface states that are protected from backscattering. The static electronic properties of these surface states have been comprehensively imaged by both photoemission and tunnelling spectroscopies. Theorists have proposed that topological surface states can also exhibit novel electronic responses to light, such as topological quantum phase transitions and spin-polarized electrical currents. However, the effects of optically driving a topological insulator out of equilibrium have remained largely unexplored experimentally, and no photocurrents have been measured. Here, we show that illuminating the topological insulator Bi2Se3 with circularly polarized light generates a photocurrent that originates from topological helical Dirac fermions, and that reversing the helicity of the light reverses the direction of the photocurrent. We also observe a photocurrent that is controlled by the linear polarization of light and argue that it may also have a topological surface state origin. This approach may allow the probing of dynamic properties of topological insulators and lead to novel opto-spintronic devices.

Original languageAmerican English
Pages (from-to)96-100
Number of pages5
JournalNature Nanotechnology
Volume7
Issue number2
DOIs
StatePublished - Feb 2012
Externally publishedYes

Bibliographical note

Funding Information:
This work was supported by the Department of Energy (DOE) (award no. DE-FG02-08ER46521), and was performed in part at the National Science Foundation (NSF) funded Harvard Center for Nanoscale Systems. Use was made of the Materials Research Science and Engineering Center Shared Experimental Facilities supported by the NSF (award no. DMR–0819762). J.W.M. acknowledges financial support from an NSF graduate research fellowship. D.H. acknowledges support from a Pappalardo postdoctoral fellowship. H.S. acknowledges support from the Israeli Ministry of Science. P.J-H. acknowledges support from a DOE Early Career Award (no. DE.SC0006418) and a Packard Fellowship.

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