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,...
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sg-ntu-dr.10356-1510212023-02-28T20:03:05Z Topological insulator metamaterial with giant circular photogalvanic effect Sun, X. Adamo, Giorgio Eginligil, Mustafa Krishnamoorthy, Harish Natarajan Swaha Zheludev, Nikolay I. Soci, Cesare School of Physical and Mathematical Sciences Centre for Disruptive Photonic Technologies (CDPT) Science::Physics Electric Insulators Electromagnetic Fields 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 (ρcirc = 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. Ministry of Education (MOE) National Research Foundation (NRF) Published version This research was supported by the Singapore Ministry of Education [grant no. MOE2016-T3-1-006 (S)], the UK Engineering and Physical Sciences Research Council (grant no.: EP/M009122/1) and the Singapore National Research Foundation, Prime Minister’s Office, under its Quantum Engineering Programme (grant no.: QEP-P1). M.E. acknowledges the 100 Foreign Talents Project in Jiangsu Province (JSA2016003) and the National Natural Science Foundation of China (NSFC 11774170) for travel support. 2021-06-25T05:31:46Z 2021-06-25T05:31:46Z 2021 Journal Article Sun, X., Adamo, G., Eginligil, M., Krishnamoorthy, H. N. S., Zheludev, N. I. & Soci, C. (2021). Topological insulator metamaterial with giant circular photogalvanic effect. Science Advances, 7(14), eabe5748-. https://dx.doi.org/10.1126/sciadv.abe5748 2375-2548 https://hdl.handle.net/10356/151021 10.1126/sciadv.abe5748 33811072 2-s2.0-85103765866 14 7 eabe5748 en MOE2016-T3-1-006 (S) QEP-P1 Science Advances 10.21979/N9/U9UXXV © 2021 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works. Distributed under a Creative Commons Attribution NonCommercial License 4.0 (CC BY-NC). application/pdf |
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Science::Physics Electric Insulators Electromagnetic Fields Sun, X. Adamo, Giorgio Eginligil, Mustafa Krishnamoorthy, Harish Natarajan Swaha Zheludev, Nikolay I. Soci, Cesare Topological insulator metamaterial with giant circular photogalvanic effect |
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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 (ρcirc = 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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School of Physical and Mathematical Sciences |
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School of Physical and Mathematical Sciences Sun, X. Adamo, Giorgio Eginligil, Mustafa Krishnamoorthy, Harish Natarajan Swaha Zheludev, Nikolay I. Soci, Cesare |
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Article |
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Sun, X. Adamo, Giorgio Eginligil, Mustafa Krishnamoorthy, Harish Natarajan Swaha Zheludev, Nikolay I. Soci, Cesare |
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Sun, X. |
title |
Topological insulator metamaterial with giant circular photogalvanic effect |
title_short |
Topological insulator metamaterial with giant circular photogalvanic effect |
title_full |
Topological insulator metamaterial with giant circular photogalvanic effect |
title_fullStr |
Topological insulator metamaterial with giant circular photogalvanic effect |
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Topological insulator metamaterial with giant circular photogalvanic effect |
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topological insulator metamaterial with giant circular photogalvanic effect |
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2021 |
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https://hdl.handle.net/10356/151021 |
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