Tuning a Circular p-n Junction in Graphene from Quantum Confinement to Optical Guiding
| Autor: | Massoud Ramezani Masir, Jinhai Mao, Eva Y. Andrei, François M. Peeters, Kenji Watanabe, Dean Moldovan, Yuhang Jiang, Guohong Li, Takashi Taniguchi |
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| Jazyk: | angličtina |
| Rok vydání: | 2017 |
| Předmět: |
Biomedical Engineering
Nanowire FOS: Physical sciences Physics::Optics Bioengineering 02 engineering and technology 01 natural sciences law.invention Resonator law 0103 physical sciences Mesoscale and Nanoscale Physics (cond-mat.mes-hall) General Materials Science Electrical and Electronic Engineering 010306 general physics Quantum tunnelling Physics Condensed matter physics Condensed Matter - Mesoscale and Nanoscale Physics business.industry Graphene Charge (physics) 021001 nanoscience & nanotechnology Condensed Matter Physics Atomic and Molecular Physics and Optics Quantum dot Optoelectronics Charge carrier 0210 nano-technology business p–n junction Engineering sciences. Technology |
| Zdroj: | Nature nanotechnology |
| ISSN: | 1748-3387 |
| Popis: | The motion of massless Dirac-electrons in graphene mimics the propagation of photons. This makes it possible to control the charge-carriers with components based on geometrical-optics and has led to proposals for an all-graphene electron-optics platform. An open question arising from the possibility of reducing the component-size to the nanometer-scale is how to access and understand the transition from optical-transport to quantum-confinement. Here we report on the realization of a circular p-n junction that can be continuously tuned from the nanometer-scale, where quantum effects are dominant, to the micrometer scale where optical-guiding takes over. We find that in the nanometer-scale junction electrons are trapped in states that resemble atomic-collapse at a supercritical charge. As the junction-size increases, the transition to optical-guiding is signaled by the emergence of whispering-gallery modes and Fabry-Perot interference. The creation of tunable junctions that straddle the crossover between quantum-confinement and optical-guiding, paves the way to novel design-architectures for controlling electronic transport. 16 pages, 4 figures |
| Databáze: | OpenAIRE |
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