Terahertz signatures of ultrafast Dirac fermion relaxation at the surface of topological insulators

Abstract Topologically protected surface states present rich physics and promising spintronic, optoelectronic, and photonic applications that require a proper understanding of their ultrafast carrier dynamics. Here, we investigate these dynamics in topological insulators (TIs) of the bismuth and ant...

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Autores principales:	S. Kovalev, K.-J. Tielrooij, J.-C. Deinert, I. Ilyakov, N. Awari, M. Chen, A. Ponomaryov, M. Bawatna, T. V. A. G. de Oliveira, L. M. Eng, K. A. Kuznetsov, D. A. Safronenkov, G. Kh. Kitaeva, P. I. Kuznetsov, H. A. Hafez, D. Turchinovich, M. Gensch
Formato:	article
Lenguaje:	EN
Publicado:	Nature Portfolio 2021
Materias:	Materials of engineering and construction. Mechanics of materials TA401-492 Atomic physics. Constitution and properties of matter QC170-197
Acceso en línea:	https://doaj.org/article/81c12363ad7c4e178f82fb0bfbb38555
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spelling	oai:doaj.org-article:81c12363ad7c4e178f82fb0bfbb385552021-12-02T17:18:12ZTerahertz signatures of ultrafast Dirac fermion relaxation at the surface of topological insulators10.1038/s41535-021-00384-92397-4648https://doaj.org/article/81c12363ad7c4e178f82fb0bfbb385552021-10-01T00:00:00Zhttps://doi.org/10.1038/s41535-021-00384-9https://doaj.org/toc/2397-4648Abstract Topologically protected surface states present rich physics and promising spintronic, optoelectronic, and photonic applications that require a proper understanding of their ultrafast carrier dynamics. Here, we investigate these dynamics in topological insulators (TIs) of the bismuth and antimony chalcogenide family, where we isolate the response of Dirac fermions at the surface from the response of bulk carriers by combining photoexcitation with below-bandgap terahertz (THz) photons and TI samples with varying Fermi level, including one sample with the Fermi level located within the bandgap. We identify distinctly faster relaxation of charge carriers in the topologically protected Dirac surface states (few hundred femtoseconds), compared to bulk carriers (few picoseconds). In agreement with such fast cooling dynamics, we observe THz harmonic generation without any saturation effects for increasing incident fields, unlike graphene which exhibits strong saturation. This opens up promising avenues for increased THz nonlinear conversion efficiencies, and high-bandwidth optoelectronic and spintronic information and communication applications.S. KovalevK.-J. TielrooijJ.-C. DeinertI. IlyakovN. AwariM. ChenA. PonomaryovM. BawatnaT. V. A. G. de OliveiraL. M. EngK. A. KuznetsovD. A. SafronenkovG. Kh. KitaevaP. I. KuznetsovH. A. HafezD. TurchinovichM. GenschNature PortfolioarticleMaterials of engineering and construction. Mechanics of materialsTA401-492Atomic physics. Constitution and properties of matterQC170-197ENnpj Quantum Materials, Vol 6, Iss 1, Pp 1-6 (2021)
institution	DOAJ
collection	DOAJ
language	EN
topic	Materials of engineering and construction. Mechanics of materials TA401-492 Atomic physics. Constitution and properties of matter QC170-197
spellingShingle	Materials of engineering and construction. Mechanics of materials TA401-492 Atomic physics. Constitution and properties of matter QC170-197 S. Kovalev K.-J. Tielrooij J.-C. Deinert I. Ilyakov N. Awari M. Chen A. Ponomaryov M. Bawatna T. V. A. G. de Oliveira L. M. Eng K. A. Kuznetsov D. A. Safronenkov G. Kh. Kitaeva P. I. Kuznetsov H. A. Hafez D. Turchinovich M. Gensch Terahertz signatures of ultrafast Dirac fermion relaxation at the surface of topological insulators
description	Abstract Topologically protected surface states present rich physics and promising spintronic, optoelectronic, and photonic applications that require a proper understanding of their ultrafast carrier dynamics. Here, we investigate these dynamics in topological insulators (TIs) of the bismuth and antimony chalcogenide family, where we isolate the response of Dirac fermions at the surface from the response of bulk carriers by combining photoexcitation with below-bandgap terahertz (THz) photons and TI samples with varying Fermi level, including one sample with the Fermi level located within the bandgap. We identify distinctly faster relaxation of charge carriers in the topologically protected Dirac surface states (few hundred femtoseconds), compared to bulk carriers (few picoseconds). In agreement with such fast cooling dynamics, we observe THz harmonic generation without any saturation effects for increasing incident fields, unlike graphene which exhibits strong saturation. This opens up promising avenues for increased THz nonlinear conversion efficiencies, and high-bandwidth optoelectronic and spintronic information and communication applications.
format	article
author	S. Kovalev K.-J. Tielrooij J.-C. Deinert I. Ilyakov N. Awari M. Chen A. Ponomaryov M. Bawatna T. V. A. G. de Oliveira L. M. Eng K. A. Kuznetsov D. A. Safronenkov G. Kh. Kitaeva P. I. Kuznetsov H. A. Hafez D. Turchinovich M. Gensch
author_facet	S. Kovalev K.-J. Tielrooij J.-C. Deinert I. Ilyakov N. Awari M. Chen A. Ponomaryov M. Bawatna T. V. A. G. de Oliveira L. M. Eng K. A. Kuznetsov D. A. Safronenkov G. Kh. Kitaeva P. I. Kuznetsov H. A. Hafez D. Turchinovich M. Gensch
author_sort	S. Kovalev
title	Terahertz signatures of ultrafast Dirac fermion relaxation at the surface of topological insulators
title_short	Terahertz signatures of ultrafast Dirac fermion relaxation at the surface of topological insulators
title_full	Terahertz signatures of ultrafast Dirac fermion relaxation at the surface of topological insulators
title_fullStr	Terahertz signatures of ultrafast Dirac fermion relaxation at the surface of topological insulators
title_full_unstemmed	Terahertz signatures of ultrafast Dirac fermion relaxation at the surface of topological insulators
title_sort	terahertz signatures of ultrafast dirac fermion relaxation at the surface of topological insulators
publisher	Nature Portfolio
publishDate	2021
url	https://doaj.org/article/81c12363ad7c4e178f82fb0bfbb38555
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Terahertz signatures of ultrafast Dirac fermion relaxation at the surface of topological insulators

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