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The wave-particle duality of electrons was tested in a closed-loop-type Aharonov-Bohm interferometer fabricated on GaAs/AlGaAs heterojunction two-dimensional electron gas system. The which-path electron detector consisted of a quantum-dot (QD) structure imbedded in one arm of the interferometer and a quantum point contact (QPC) located in proximity to the QD. The quantum point contact coupled to the quantum dot detects the presence of the charge inside the quantum dot to give the path information of the electron inside the interferometer. The which-path detection is inevitably coupled to the interferometer and the environments, leading to dephasing in the traversing electron state. This thus results in the suppression of the interference of conducting electrons, the manifestation of a wave nature of the particles.. In this work, observation similar to the one using an open-loop-type electron interferometer [1] was carried out in a closed-loop-type electron interferometer to obtain more detailed information on the dephasing mechanism and its origin. Especiallly, dephasing of electrons circulating multiple times inside the interferometer was studied in depth. This study confirms that the which-path detection is the real cause of the dephasing.
[1] E. Buks, R. Schuster, M. Heiblum, D. Mahalu and V. Umansky, Nature 391, 871 (1998) |
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