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Quantum size effect on charges and phonons ultrafast dynamics in atomically controlled nanolayers of topological insulators Bi(2)Te(3)

Heralded as one of the key elements for next generation spintronics devices, topological insulators (TIs) are now step by step envisioned as nanodevices like charge-to-spin current conversion or as Dirac fermions based nanometer Schottky diode for example. However, reduced to few nanometers, TIs lay...

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Autores principales: Weis, M., Wilk, B., Vaudel, G., Balin, K., Rapacz, R., Bulou, A., Arnaud, B., Szade, J., Ruello, P.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Nature Publishing Group UK 2017
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5653873/
https://www.ncbi.nlm.nih.gov/pubmed/29061972
http://dx.doi.org/10.1038/s41598-017-12920-4
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author Weis, M.
Wilk, B.
Vaudel, G.
Balin, K.
Rapacz, R.
Bulou, A.
Arnaud, B.
Szade, J.
Ruello, P.
author_facet Weis, M.
Wilk, B.
Vaudel, G.
Balin, K.
Rapacz, R.
Bulou, A.
Arnaud, B.
Szade, J.
Ruello, P.
author_sort Weis, M.
collection PubMed
description Heralded as one of the key elements for next generation spintronics devices, topological insulators (TIs) are now step by step envisioned as nanodevices like charge-to-spin current conversion or as Dirac fermions based nanometer Schottky diode for example. However, reduced to few nanometers, TIs layers exhibit a profound modification of the electronic structure and the consequence of this quantum size effect on the fundamental carriers and phonons ultrafast dynamics has been poorly investigated so far. Here, thanks to a complete study of a set of high quality molecular beam epitaxy grown nanolayers, we report the existence of a critical thickness of around ~6 nm, below which a spectacular reduction of the carrier relaxation time by a factor of ten is found in comparison to bulk Bi(2) Te(3) In addition, we also evidence an A1g optical phonon mode softening together with the appearance of a thickness dependence of the photoinduced coherent acoustic phonons signals. This drastic evolution of the carriers and phonons dynamics might be due an important electron-phonon coupling evolution due to the quantum confinement. These properties have to be taken into account for future TIs-based spintronic devices.
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spelling pubmed-56538732017-11-08 Quantum size effect on charges and phonons ultrafast dynamics in atomically controlled nanolayers of topological insulators Bi(2)Te(3) Weis, M. Wilk, B. Vaudel, G. Balin, K. Rapacz, R. Bulou, A. Arnaud, B. Szade, J. Ruello, P. Sci Rep Article Heralded as one of the key elements for next generation spintronics devices, topological insulators (TIs) are now step by step envisioned as nanodevices like charge-to-spin current conversion or as Dirac fermions based nanometer Schottky diode for example. However, reduced to few nanometers, TIs layers exhibit a profound modification of the electronic structure and the consequence of this quantum size effect on the fundamental carriers and phonons ultrafast dynamics has been poorly investigated so far. Here, thanks to a complete study of a set of high quality molecular beam epitaxy grown nanolayers, we report the existence of a critical thickness of around ~6 nm, below which a spectacular reduction of the carrier relaxation time by a factor of ten is found in comparison to bulk Bi(2) Te(3) In addition, we also evidence an A1g optical phonon mode softening together with the appearance of a thickness dependence of the photoinduced coherent acoustic phonons signals. This drastic evolution of the carriers and phonons dynamics might be due an important electron-phonon coupling evolution due to the quantum confinement. These properties have to be taken into account for future TIs-based spintronic devices. Nature Publishing Group UK 2017-10-23 /pmc/articles/PMC5653873/ /pubmed/29061972 http://dx.doi.org/10.1038/s41598-017-12920-4 Text en © The Author(s) 2017 Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/.
spellingShingle Article
Weis, M.
Wilk, B.
Vaudel, G.
Balin, K.
Rapacz, R.
Bulou, A.
Arnaud, B.
Szade, J.
Ruello, P.
Quantum size effect on charges and phonons ultrafast dynamics in atomically controlled nanolayers of topological insulators Bi(2)Te(3)
title Quantum size effect on charges and phonons ultrafast dynamics in atomically controlled nanolayers of topological insulators Bi(2)Te(3)
title_full Quantum size effect on charges and phonons ultrafast dynamics in atomically controlled nanolayers of topological insulators Bi(2)Te(3)
title_fullStr Quantum size effect on charges and phonons ultrafast dynamics in atomically controlled nanolayers of topological insulators Bi(2)Te(3)
title_full_unstemmed Quantum size effect on charges and phonons ultrafast dynamics in atomically controlled nanolayers of topological insulators Bi(2)Te(3)
title_short Quantum size effect on charges and phonons ultrafast dynamics in atomically controlled nanolayers of topological insulators Bi(2)Te(3)
title_sort quantum size effect on charges and phonons ultrafast dynamics in atomically controlled nanolayers of topological insulators bi(2)te(3)
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5653873/
https://www.ncbi.nlm.nih.gov/pubmed/29061972
http://dx.doi.org/10.1038/s41598-017-12920-4
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