Helicity dependent photocurrent in electrically gated (Bi1−x Sb x )2Te3 thin films

Yu Pan, Qing-Ze Wang, Andrew L. Yeats, Timothy Pillsbury, Thomas C. Flanagan, Anthony Richardella, Haijun Zhang, David D. Awschalom, Chao-Xing Liu and Nitin Samarth ()
Additional contact information
Yu Pan: The Pennsylvania State University
Qing-Ze Wang: The Pennsylvania State University
Andrew L. Yeats: University of Chicago
Timothy Pillsbury: The Pennsylvania State University
Thomas C. Flanagan: The Pennsylvania State University
Anthony Richardella: The Pennsylvania State University
Haijun Zhang: Nanjing University
David D. Awschalom: University of Chicago
Chao-Xing Liu: The Pennsylvania State University
Nitin Samarth: The Pennsylvania State University

Nature Communications, 2017, vol. 8, issue 1, 1-9

Abstract: Abstract Circularly polarized photons are known to generate a directional helicity-dependent photocurrent in three-dimensional topological insulators at room temperature. Surprisingly, the phenomenon is readily observed at photon energies that excite electrons to states far above the spin-momentum locked Dirac cone and the underlying mechanism for the helicity-dependent photocurrent is still not understood. Here we show a comprehensive study of the helicity-dependent photocurrent in (Bi1−x Sb x )2Te3 thin films as a function of the incidence angle of the optical excitation, its wavelength and the gate-tuned chemical potential. Our observations allow us to unambiguously identify the circular photo-galvanic effect as the dominant mechanism for the helicity-dependent photocurrent. Additionally, we use an analytical model to relate the directional nature of the photocurrent to asymmetric optical transitions between the topological surface states and bulk bands. The insights we obtain are important for engineering opto-spintronic devices that rely on optical steering of spin and charge currents.

Date: 2017
References: Add references at CitEc
Citations: View citations in EconPapers (1)

Downloads: (external link)
https://www.nature.com/articles/s41467-017-00711-4 Abstract (text/html)

Related works:
This item may be available elsewhere in EconPapers: Search for items with the same title.

Export reference: BibTeX RIS (EndNote, ProCite, RefMan) HTML/Text

Persistent link: https://EconPapers.repec.org/RePEc:nat:natcom:v:8:y:2017:i:1:d:10.1038_s41467-017-00711-4

Ordering information: This journal article can be ordered from
https://www.nature.com/ncomms/

DOI: 10.1038/s41467-017-00711-4

Access Statistics for this article

Nature Communications is currently edited by Nathalie Le Bot, Enda Bergin and Fiona Gillespie

More articles in Nature Communications from Nature
Bibliographic data for series maintained by Sonal Shukla () and Springer Nature Abstracting and Indexing ().