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Specular Electron Focusing between Gate-Defined Quantum Point Contacts in Bilayer Graphene

[Image: see text] We report multiterminal measurements in a ballistic bilayer graphene (BLG) channel, where multiple spin- and valley-degenerate quantum point contacts (QPCs) are defined by electrostatic gating. By patterning QPCs of different shapes along different crystallographic directions, we s...

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Autores principales: Ingla-Aynés, Josep, Manesco, Antonio L. R., Ghiasi, Talieh S., Volosheniuk, Serhii, Watanabe, Kenji, Taniguchi, Takashi, van der Zant, Herre S. J.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: American Chemical Society 2023
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10311585/
https://www.ncbi.nlm.nih.gov/pubmed/37289250
http://dx.doi.org/10.1021/acs.nanolett.3c00499
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author Ingla-Aynés, Josep
Manesco, Antonio L. R.
Ghiasi, Talieh S.
Volosheniuk, Serhii
Watanabe, Kenji
Taniguchi, Takashi
van der Zant, Herre S. J.
author_facet Ingla-Aynés, Josep
Manesco, Antonio L. R.
Ghiasi, Talieh S.
Volosheniuk, Serhii
Watanabe, Kenji
Taniguchi, Takashi
van der Zant, Herre S. J.
author_sort Ingla-Aynés, Josep
collection PubMed
description [Image: see text] We report multiterminal measurements in a ballistic bilayer graphene (BLG) channel, where multiple spin- and valley-degenerate quantum point contacts (QPCs) are defined by electrostatic gating. By patterning QPCs of different shapes along different crystallographic directions, we study the effect of size quantization and trigonal warping on transverse electron focusing (TEF). Our TEF spectra show eight clear peaks with comparable amplitudes and weak signatures of quantum interference at the lowest temperature, indicating that reflections at the gate-defined edges are specular, and transport is phase coherent. The temperature dependence of the focusing signal shows that, despite the small gate-induced bandgaps in our sample (≲45 meV), several peaks are visible up to 100 K. The achievement of specular reflection, which is expected to preserve the pseudospin information of the electron jets, is promising for the realization of ballistic interconnects for new valleytronic devices.
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spelling pubmed-103115852023-07-01 Specular Electron Focusing between Gate-Defined Quantum Point Contacts in Bilayer Graphene Ingla-Aynés, Josep Manesco, Antonio L. R. Ghiasi, Talieh S. Volosheniuk, Serhii Watanabe, Kenji Taniguchi, Takashi van der Zant, Herre S. J. Nano Lett [Image: see text] We report multiterminal measurements in a ballistic bilayer graphene (BLG) channel, where multiple spin- and valley-degenerate quantum point contacts (QPCs) are defined by electrostatic gating. By patterning QPCs of different shapes along different crystallographic directions, we study the effect of size quantization and trigonal warping on transverse electron focusing (TEF). Our TEF spectra show eight clear peaks with comparable amplitudes and weak signatures of quantum interference at the lowest temperature, indicating that reflections at the gate-defined edges are specular, and transport is phase coherent. The temperature dependence of the focusing signal shows that, despite the small gate-induced bandgaps in our sample (≲45 meV), several peaks are visible up to 100 K. The achievement of specular reflection, which is expected to preserve the pseudospin information of the electron jets, is promising for the realization of ballistic interconnects for new valleytronic devices. American Chemical Society 2023-06-08 /pmc/articles/PMC10311585/ /pubmed/37289250 http://dx.doi.org/10.1021/acs.nanolett.3c00499 Text en © 2023 The Authors. Published by American Chemical Society https://creativecommons.org/licenses/by/4.0/Permits the broadest form of re-use including for commercial purposes, provided that author attribution and integrity are maintained (https://creativecommons.org/licenses/by/4.0/).
spellingShingle Ingla-Aynés, Josep
Manesco, Antonio L. R.
Ghiasi, Talieh S.
Volosheniuk, Serhii
Watanabe, Kenji
Taniguchi, Takashi
van der Zant, Herre S. J.
Specular Electron Focusing between Gate-Defined Quantum Point Contacts in Bilayer Graphene
title Specular Electron Focusing between Gate-Defined Quantum Point Contacts in Bilayer Graphene
title_full Specular Electron Focusing between Gate-Defined Quantum Point Contacts in Bilayer Graphene
title_fullStr Specular Electron Focusing between Gate-Defined Quantum Point Contacts in Bilayer Graphene
title_full_unstemmed Specular Electron Focusing between Gate-Defined Quantum Point Contacts in Bilayer Graphene
title_short Specular Electron Focusing between Gate-Defined Quantum Point Contacts in Bilayer Graphene
title_sort specular electron focusing between gate-defined quantum point contacts in bilayer graphene
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10311585/
https://www.ncbi.nlm.nih.gov/pubmed/37289250
http://dx.doi.org/10.1021/acs.nanolett.3c00499
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