Imaging electrostatically confined Dirac fermions in graphene quantum dots
Electrostatic confinement of charge carriers in graphene is governed by Klein tunnelling, a relativistic quantum process in which particle–hole transmutation leads to unusual anisotropic transmission at p–n junction boundaries. Reflection and transmission at these boundaries affect the quantum inter...
| Main Authors: | , , , , , , , , , , , |
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| Format: | Article |
| Language: | en_US |
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Nature Publishing Group
2017
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| Online Access: | http://hdl.handle.net/1721.1/110015 https://orcid.org/0000-0002-3023-396X https://orcid.org/0000-0002-4268-731X |
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| author | Lee, Juwon Wong, Dillon Velasco Jr, Jairo Kahn, Salman Tsai, Hsin-Zon Taniguchi, Takashi Watanabe, Kenji Zettl, Alex Wang, Feng Crommie, Michael F. Rodriguez Nieva, Joaquin Francisco Levitov, Leonid |
| author2 | Massachusetts Institute of Technology. Department of Physics |
| author_facet | Massachusetts Institute of Technology. Department of Physics Lee, Juwon Wong, Dillon Velasco Jr, Jairo Kahn, Salman Tsai, Hsin-Zon Taniguchi, Takashi Watanabe, Kenji Zettl, Alex Wang, Feng Crommie, Michael F. Rodriguez Nieva, Joaquin Francisco Levitov, Leonid |
| author_sort | Lee, Juwon |
| collection | MIT |
| description | Electrostatic confinement of charge carriers in graphene is governed by Klein tunnelling, a relativistic quantum process in which particle–hole transmutation leads to unusual anisotropic transmission at p–n junction boundaries. Reflection and transmission at these boundaries affect the quantum interference of electronic waves, enabling the formation of novel quasi-bound states. Here we report the use of scanning tunnelling microscopy to map the electronic structure of Dirac fermions confined in quantum dots defined by circular graphene p–n junctions. The quantum dots were fabricated using a technique involving local manipulation of defect charge within the insulating substrate beneath a graphene monolayer13. Inside such graphene quantum dots we observe resonances due to quasi-bound states and directly visualize the quantum interference patterns arising from these states. Outside the quantum dots Dirac fermions exhibit Friedel oscillation-like behaviour. Bolstered by a theoretical model describing relativistic particles in a harmonic oscillator potential, our findings yield insights into the spatial behaviour of electrostatically confined Dirac fermions. |
| first_indexed | 2024-09-23T08:15:56Z |
| format | Article |
| id | mit-1721.1/110015 |
| institution | Massachusetts Institute of Technology |
| language | en_US |
| last_indexed | 2024-09-23T08:15:56Z |
| publishDate | 2017 |
| publisher | Nature Publishing Group |
| record_format | dspace |
| spelling | mit-1721.1/1100152022-09-30T08:42:32Z Imaging electrostatically confined Dirac fermions in graphene quantum dots Lee, Juwon Wong, Dillon Velasco Jr, Jairo Kahn, Salman Tsai, Hsin-Zon Taniguchi, Takashi Watanabe, Kenji Zettl, Alex Wang, Feng Crommie, Michael F. Rodriguez Nieva, Joaquin Francisco Levitov, Leonid Massachusetts Institute of Technology. Department of Physics Rodriguez Nieva, Joaquin Francisco Levitov, Leonid Electrostatic confinement of charge carriers in graphene is governed by Klein tunnelling, a relativistic quantum process in which particle–hole transmutation leads to unusual anisotropic transmission at p–n junction boundaries. Reflection and transmission at these boundaries affect the quantum interference of electronic waves, enabling the formation of novel quasi-bound states. Here we report the use of scanning tunnelling microscopy to map the electronic structure of Dirac fermions confined in quantum dots defined by circular graphene p–n junctions. The quantum dots were fabricated using a technique involving local manipulation of defect charge within the insulating substrate beneath a graphene monolayer13. Inside such graphene quantum dots we observe resonances due to quasi-bound states and directly visualize the quantum interference patterns arising from these states. Outside the quantum dots Dirac fermions exhibit Friedel oscillation-like behaviour. Bolstered by a theoretical model describing relativistic particles in a harmonic oscillator potential, our findings yield insights into the spatial behaviour of electrostatically confined Dirac fermions. United States. Department of Energy. Office of Basic Energy Sciences (Contract DE-AC02-05CH11231) National Science Foundation (U.S.) (Award CMMI-1206512) 2017-06-19T16:43:31Z 2017-06-19T16:43:31Z 2016-06 2016-02 Article http://purl.org/eprint/type/JournalArticle 1745-2473 1745-2481 http://hdl.handle.net/1721.1/110015 Lee, Juwon et al. “Imaging Electrostatically Confined Dirac Fermions in Graphene Quantum Dots.” Nature Physics 12.11 (2016): 1032–1036. https://orcid.org/0000-0002-3023-396X https://orcid.org/0000-0002-4268-731X en_US http://dx.doi.org/10.1038/nphys3805 Nature Physics Creative Commons Attribution-Noncommercial-Share Alike http://creativecommons.org/licenses/by-nc-sa/4.0/ application/pdf Nature Publishing Group arXiv |
| spellingShingle | Lee, Juwon Wong, Dillon Velasco Jr, Jairo Kahn, Salman Tsai, Hsin-Zon Taniguchi, Takashi Watanabe, Kenji Zettl, Alex Wang, Feng Crommie, Michael F. Rodriguez Nieva, Joaquin Francisco Levitov, Leonid Imaging electrostatically confined Dirac fermions in graphene quantum dots |
| title | Imaging electrostatically confined Dirac fermions in graphene quantum dots |
| title_full | Imaging electrostatically confined Dirac fermions in graphene quantum dots |
| title_fullStr | Imaging electrostatically confined Dirac fermions in graphene quantum dots |
| title_full_unstemmed | Imaging electrostatically confined Dirac fermions in graphene quantum dots |
| title_short | Imaging electrostatically confined Dirac fermions in graphene quantum dots |
| title_sort | imaging electrostatically confined dirac fermions in graphene quantum dots |
| url | http://hdl.handle.net/1721.1/110015 https://orcid.org/0000-0002-3023-396X https://orcid.org/0000-0002-4268-731X |
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