Tunnelling spectroscopy of Andreev states in graphene
A normal conductor placed in good contact with a superconductor can inherit its remarkable electronic properties1,2. This proximity effect microscopically originates from the formation in the conductor of entangled electron-hole states, called Andreev states3-8. Spectroscopic studies of Andreev stat...
| Main Authors: | , , , , , |
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| Format: | Article |
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Springer Nature
2019
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| Online Access: | https://hdl.handle.net/1721.1/121327 |
| _version_ | 1811078994140856320 |
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| author | Bretheau, Landry Wang, Joel I-Jan Pisoni, Riccardo Watanabe, Kenji Taniguchi, Takashi Jarillo-Herrero, Pablo |
| author2 | Massachusetts Institute of Technology. Department of Physics |
| author_facet | Massachusetts Institute of Technology. Department of Physics Bretheau, Landry Wang, Joel I-Jan Pisoni, Riccardo Watanabe, Kenji Taniguchi, Takashi Jarillo-Herrero, Pablo |
| author_sort | Bretheau, Landry |
| collection | MIT |
| description | A normal conductor placed in good contact with a superconductor can inherit its remarkable electronic properties1,2. This proximity effect microscopically originates from the formation in the conductor of entangled electron-hole states, called Andreev states3-8. Spectroscopic studies of Andreev states have been performed in just a handful of systems9-13. The unique geometry, electronic structure and high mobility of graphene14,15 make it a novel platform for studying Andreev physics in two dimensions. Here we use a full van der Waals heterostructure to perform tunnelling spectroscopy measurements of the proximity effect in superconductor-graphene- superconductorjunctions.Themeasuredenergyspectra,which depend on the phase difference between the superconductors, reveal the presence of a continuum of Andreev bound states. Moreover, our device heterostructure geometry and materials enable us to measure the Andreev spectrum as a function of the graphene Fermi energy, showing a transition between different mesoscopic regimes. Furthermore, by experimentally introducing a novel concept, the supercurrent spectral density, we determine the supercurrent-phase relation in a tunnelling experiment,thusestablishingtheconnectionbetweenAndreev physics at finite energy and the Josephson effect. This work opens up new avenues for probing exotic topological phases of matter in hybrid superconducting Dirac materials 16-18 . |
| first_indexed | 2024-09-23T11:08:29Z |
| format | Article |
| id | mit-1721.1/121327 |
| institution | Massachusetts Institute of Technology |
| last_indexed | 2024-09-23T11:08:29Z |
| publishDate | 2019 |
| publisher | Springer Nature |
| record_format | dspace |
| spelling | mit-1721.1/1213272022-10-01T01:33:55Z Tunnelling spectroscopy of Andreev states in graphene Bretheau, Landry Wang, Joel I-Jan Pisoni, Riccardo Watanabe, Kenji Taniguchi, Takashi Jarillo-Herrero, Pablo Massachusetts Institute of Technology. Department of Physics A normal conductor placed in good contact with a superconductor can inherit its remarkable electronic properties1,2. This proximity effect microscopically originates from the formation in the conductor of entangled electron-hole states, called Andreev states3-8. Spectroscopic studies of Andreev states have been performed in just a handful of systems9-13. The unique geometry, electronic structure and high mobility of graphene14,15 make it a novel platform for studying Andreev physics in two dimensions. Here we use a full van der Waals heterostructure to perform tunnelling spectroscopy measurements of the proximity effect in superconductor-graphene- superconductorjunctions.Themeasuredenergyspectra,which depend on the phase difference between the superconductors, reveal the presence of a continuum of Andreev bound states. Moreover, our device heterostructure geometry and materials enable us to measure the Andreev spectrum as a function of the graphene Fermi energy, showing a transition between different mesoscopic regimes. Furthermore, by experimentally introducing a novel concept, the supercurrent spectral density, we determine the supercurrent-phase relation in a tunnelling experiment,thusestablishingtheconnectionbetweenAndreev physics at finite energy and the Josephson effect. This work opens up new avenues for probing exotic topological phases of matter in hybrid superconducting Dirac materials 16-18 . United States. Department of Energy (Grant DE-SC0001819) Gordon and Betty Moore Foundation (Grant GBMF4541) 2019-06-17T17:47:32Z 2019-06-17T17:47:32Z 2017-05 2017-01 2019-03-27T13:14:39Z Article http://purl.org/eprint/type/JournalArticle 1745-2473 1745-2481 https://hdl.handle.net/1721.1/121327 Bretheau, Landry et al. “Tunnelling Spectroscopy of Andreev States in Graphene.” Nature Physics 13, 8 (May 2017): 756–760 © 2017 Macmillan Publishers Limited, part of Springer Nature http://dx.doi.org/10.1038/NPHYS4110 Nature Physics Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. application/pdf Springer Nature arXiv |
| spellingShingle | Bretheau, Landry Wang, Joel I-Jan Pisoni, Riccardo Watanabe, Kenji Taniguchi, Takashi Jarillo-Herrero, Pablo Tunnelling spectroscopy of Andreev states in graphene |
| title | Tunnelling spectroscopy of Andreev states in graphene |
| title_full | Tunnelling spectroscopy of Andreev states in graphene |
| title_fullStr | Tunnelling spectroscopy of Andreev states in graphene |
| title_full_unstemmed | Tunnelling spectroscopy of Andreev states in graphene |
| title_short | Tunnelling spectroscopy of Andreev states in graphene |
| title_sort | tunnelling spectroscopy of andreev states in graphene |
| url | https://hdl.handle.net/1721.1/121327 |
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