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Murani A, Dassonneville B, Kasumov A, Basset J, Ferrier M, Deblock R, Guéron S, Bouchiat H. Microwave Signature of Topological Andreev level Crossings in a Bismuth-based Josephson Junction. Phys Rev Lett 2019; 122:076802. [PMID: 30848609 DOI: 10.1103/physrevlett.122.076802] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2018] [Indexed: 06/09/2023]
Abstract
Demonstrating the topological protection of Andreev states in Josephson junctions is an experimental challenge. In particular the telltale 4π periodicity expected for the current phase relation has remained elusive, because of fast parity breaking processes. It was predicted that low temperature ac susceptibility measurements could reveal the topological protection of quantum spin Hall edge states by probing their low energy Andreev spectrum at finite frequency. We have performed such a microwave probing of a phase-biased Josephson junction built around a bismuth nanowire, a predicted second order topological insulator, and which was previously shown to host one-dimensional ballistic edge states. We find absorption peaks at the Andreev level crossings, whose temperature and frequency dependencies point to protected topological crossings with an accuracy limited by the electronic temperature of our experiment.
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Affiliation(s)
- A Murani
- Laboratoire de Physique des Solides, CNRS, Université Paris-Sud, Université Paris-Saclay, 91405 Orsay Cedex, France
- Quantronics Group, Service de Physique de l'État Condensé (CNRS UMR 3680), IRAMIS, CEA-Saclay, 91191 Gif-sur-Yvette, France
| | - B Dassonneville
- Laboratoire de Physique des Solides, CNRS, Université Paris-Sud, Université Paris-Saclay, 91405 Orsay Cedex, France
| | - A Kasumov
- Laboratoire de Physique des Solides, CNRS, Université Paris-Sud, Université Paris-Saclay, 91405 Orsay Cedex, France
| | - J Basset
- Laboratoire de Physique des Solides, CNRS, Université Paris-Sud, Université Paris-Saclay, 91405 Orsay Cedex, France
| | - M Ferrier
- Laboratoire de Physique des Solides, CNRS, Université Paris-Sud, Université Paris-Saclay, 91405 Orsay Cedex, France
| | - R Deblock
- Laboratoire de Physique des Solides, CNRS, Université Paris-Sud, Université Paris-Saclay, 91405 Orsay Cedex, France
| | - S Guéron
- Laboratoire de Physique des Solides, CNRS, Université Paris-Sud, Université Paris-Saclay, 91405 Orsay Cedex, France
| | - H Bouchiat
- Laboratoire de Physique des Solides, CNRS, Université Paris-Sud, Université Paris-Saclay, 91405 Orsay Cedex, France
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Dufouleur J, Veyrat L, Dassonneville B, Xypakis E, Bardarson JH, Nowka C, Hampel S, Schumann J, Eichler B, Schmidt OG, Büchner B, Giraud R. Weakly-coupled quasi-1D helical modes in disordered 3D topological insulator quantum wires. Sci Rep 2017; 7:45276. [PMID: 28374744 PMCID: PMC5379752 DOI: 10.1038/srep45276] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2016] [Accepted: 02/23/2017] [Indexed: 11/12/2022] Open
Abstract
Disorder remains a key limitation in the search for robust signatures of topological superconductivity in condensed matter. Whereas clean semiconducting quantum wires gave promising results discussed in terms of Majorana bound states, disorder makes the interpretation more complex. Quantum wires of 3D topological insulators offer a serious alternative due to their perfectly-transmitted mode. An important aspect to consider is the mixing of quasi-1D surface modes due to the strong degree of disorder typical for such materials. Here, we reveal that the energy broadening γ of such modes is much smaller than their energy spacing Δ, an unusual result for highly-disordered mesoscopic nanostructures. This is evidenced by non-universal conductance fluctuations in highly-doped and disordered Bi2Se3 and Bi2Te3 nanowires. Theory shows that such a unique behavior is specific to spin-helical Dirac fermions with strong quantum confinement, which retain ballistic properties over an unusually large energy scale due to their spin texture. Our result confirms their potential to investigate topological superconductivity without ambiguity despite strong disorder.
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Affiliation(s)
- J Dufouleur
- Leibniz Institute for Solid State and Materials Research, IFW Dresden, D-01069 Dresden, Germany
| | - L Veyrat
- Leibniz Institute for Solid State and Materials Research, IFW Dresden, D-01069 Dresden, Germany
| | - B Dassonneville
- Leibniz Institute for Solid State and Materials Research, IFW Dresden, D-01069 Dresden, Germany
| | - E Xypakis
- Max-Planck-Institut für Physik Komplexer Systeme, Nöthnitzer Straße 38, D-01187 Dresden, Germany
| | - J H Bardarson
- Max-Planck-Institut für Physik Komplexer Systeme, Nöthnitzer Straße 38, D-01187 Dresden, Germany
| | - C Nowka
- Leibniz Institute for Solid State and Materials Research, IFW Dresden, D-01069 Dresden, Germany
| | - S Hampel
- Leibniz Institute for Solid State and Materials Research, IFW Dresden, D-01069 Dresden, Germany
| | - J Schumann
- Leibniz Institute for Solid State and Materials Research, IFW Dresden, D-01069 Dresden, Germany
| | - B Eichler
- Leibniz Institute for Solid State and Materials Research, IFW Dresden, D-01069 Dresden, Germany
| | - O G Schmidt
- Leibniz Institute for Solid State and Materials Research, IFW Dresden, D-01069 Dresden, Germany
| | - B Büchner
- Leibniz Institute for Solid State and Materials Research, IFW Dresden, D-01069 Dresden, Germany.,Department of Physics, TU Dresden, D-01062 Dresden, Germany
| | - R Giraud
- Leibniz Institute for Solid State and Materials Research, IFW Dresden, D-01069 Dresden, Germany.,INAC-SPINTEC, Univ. Grenoble Alpes/CNRS/CEA, 17 Avenue des Martyrs, F-38054 Grenoble, France
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Dufouleur J, Veyrat L, Dassonneville B, Nowka C, Hampel S, Leksin P, Eichler B, Schmidt OG, Büchner B, Giraud R. Correction to Enhanced Mobility of Spin-Helical Dirac Fermions in Disordered 3D Topological Insulators. Nano Lett 2017; 17:597. [PMID: 28009173 DOI: 10.1021/acs.nanolett.6b05051] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
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Dufouleur J, Veyrat L, Dassonneville B, Nowka C, Hampel S, Leksin P, Eichler B, Schmidt OG, Büchner B, Giraud R. Enhanced Mobility of Spin-Helical Dirac Fermions in Disordered 3D Topological Insulators. Nano Lett 2016; 16:6733-6737. [PMID: 27706936 DOI: 10.1021/acs.nanolett.6b02060] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The transport length ltr and the mean free path le are determined for bulk and surface states in a Bi2Se3 nanoribbon by quantum transport and transconductance measurements. We show that the anisotropic scattering of spin-helical Dirac fermions results in a strong enhancement of ltr (≈ 200 nm) and of the related mobility μtr (≈ 4000 cm2 V-1 s-1), which confirms theoretical predictions.1 Despite strong disorder, the long-range nature of the scattering potential gives a large ratio ltr/le ≈ 8, likely limited by bulk/surface coupling. This suggests that the spin-flip length lsf ≈ ltr could reach the micron size in materials with a reduced bulk doping and paves the way for building functionalized spintronic and ballistic electronic devices out of disordered 3D topological insulators.
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Affiliation(s)
| | - Louis Veyrat
- IFW Dresden , P.O. Box 270116, D-01171 Dresden, Germany
| | | | | | - Silke Hampel
- IFW Dresden , P.O. Box 270116, D-01171 Dresden, Germany
| | - Pavel Leksin
- IFW Dresden , P.O. Box 270116, D-01171 Dresden, Germany
| | | | | | - Bernd Büchner
- IFW Dresden , P.O. Box 270116, D-01171 Dresden, Germany
| | - Romain Giraud
- IFW Dresden , P.O. Box 270116, D-01171 Dresden, Germany
- INAC-SPINTEC, Univ. Grenoble Alpes/CNRS/CEA , 17 Avenue des Martyrs, 38054 Grenoble, France
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Dassonneville B, Ferrier M, Guéron S, Bouchiat H. Dissipation and supercurrent fluctuations in a diffusive normal-metal-superconductor ring. Phys Rev Lett 2013; 110:217001. [PMID: 23745912 DOI: 10.1103/physrevlett.110.217001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2013] [Indexed: 06/02/2023]
Abstract
A mesoscopic hybrid normal-metal-superconductor ring is characterized by a dense Andreev spectrum with a flux dependent minigap. To probe the dynamics of such a ring, we measure its linear response to a high frequency flux, in a wide frequency range, with a multimode superconducting resonator. We find that the current response contains, besides the well-known dissipationless Josephson contribution, a large dissipative component. At high frequency compared to the minigap and low temperature, we find that the dissipation is due to transitions across the minigap. In contrast, at lower frequency there is a range of temperature for which dissipation is caused predominantly by the relaxation of the Andreev states' population. This dissipative response, related via the fluctuation dissipation theorem to a nonintuitive zero frequency thermal noise of supercurrent, is characterized by a phase dependence dominated by its second harmonic, as predicted long ago but never observed thus far.
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Affiliation(s)
- B Dassonneville
- LPS, University of Paris-Sud, CNRS, UMR 8502, F-91405 Orsay Cedex, France
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