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Topological insulator metamaterial with giant circular photogalvanic effect

Topological insulator metamaterial with giant circular photogalvanic effect
Topological insulator metamaterial with giant circular photogalvanic effect
One of the most notable manifestations of electronic properties of topological insulators is the dependence of the photocurrent direction on the helicity of circularly polarized optical excitation. The helicity-dependent photocurrents, underpinned by spin-momentum locking of surface Dirac electrons, are weak and easily overshadowed by bulk contributions. Here, we show that the chiral response can be enhanced by nanostructuring. The tight confinement
of electromagnetic fields in the resonant nanostructure enhances the photoexcitation of spin-polarized surface states of topological insulator Bi1.5Sb0.5Te1.8Se1.2, leading to an 11-fold increase of the circular photogalvanic effect and a previously unobserved photocurrent dichroism (circ = 0.87) at room temperature. The control of spin transport in topological materials by structural design is a previously unrecognized ability of metamaterials that bridges the gap between nanophotonics and spin electronics, providing opportunities for developing polarization-sensitive photodetectors.
2375-2548
Sun, Xinxing
2264494f-f425-4d5c-94bf-eebc150f5796
Adamo, Giorgio
8c4da92b-f849-42d4-99c8-b0eb4ba1c73a
Eginligil, Mustafa
924cfd95-0524-4877-b684-7c6a338f6543
Krishnamoorthy, Harish N.S.
87456c53-9077-4ccf-80b9-44470ad845b9
Zheludev, Nikolai
32fb6af7-97e4-4d11-bca6-805745e40cc6
Soci, Cesare
cab44ec8-b119-4f74-bf3b-5b110e57cfed
Sun, Xinxing
2264494f-f425-4d5c-94bf-eebc150f5796
Adamo, Giorgio
8c4da92b-f849-42d4-99c8-b0eb4ba1c73a
Eginligil, Mustafa
924cfd95-0524-4877-b684-7c6a338f6543
Krishnamoorthy, Harish N.S.
87456c53-9077-4ccf-80b9-44470ad845b9
Zheludev, Nikolai
32fb6af7-97e4-4d11-bca6-805745e40cc6
Soci, Cesare
cab44ec8-b119-4f74-bf3b-5b110e57cfed

Sun, Xinxing, Adamo, Giorgio, Eginligil, Mustafa, Krishnamoorthy, Harish N.S., Zheludev, Nikolai and Soci, Cesare (2021) Topological insulator metamaterial with giant circular photogalvanic effect. Science Advances, 7 (14), [eabe5748].

Record type: Article

Abstract

One of the most notable manifestations of electronic properties of topological insulators is the dependence of the photocurrent direction on the helicity of circularly polarized optical excitation. The helicity-dependent photocurrents, underpinned by spin-momentum locking of surface Dirac electrons, are weak and easily overshadowed by bulk contributions. Here, we show that the chiral response can be enhanced by nanostructuring. The tight confinement
of electromagnetic fields in the resonant nanostructure enhances the photoexcitation of spin-polarized surface states of topological insulator Bi1.5Sb0.5Te1.8Se1.2, leading to an 11-fold increase of the circular photogalvanic effect and a previously unobserved photocurrent dichroism (circ = 0.87) at room temperature. The control of spin transport in topological materials by structural design is a previously unrecognized ability of metamaterials that bridges the gap between nanophotonics and spin electronics, providing opportunities for developing polarization-sensitive photodetectors.

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Sun-2021-SCA-Topological Insulator - Version of Record
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Published date: 21 April 2021

Identifiers

Local EPrints ID: 449614
URI: http://eprints.soton.ac.uk/id/eprint/449614
ISSN: 2375-2548
PURE UUID: 491c5d49-e884-4242-ab6e-dcc22b6be841
ORCID for Nikolai Zheludev: ORCID iD orcid.org/0000-0002-1013-6636

Catalogue record

Date deposited: 09 Jun 2021 16:30
Last modified: 26 Nov 2021 02:36

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Contributors

Author: Xinxing Sun
Author: Giorgio Adamo
Author: Mustafa Eginligil
Author: Harish N.S. Krishnamoorthy
Author: Cesare Soci

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