title: Coherent tunnelling across a quantum point contact in the quantum Hall regime.
abstract: The unique properties of quantum hall devices arise from the ideal one-dimensional edge states that form in a two-dimensional electron system at high magnetic field. Tunnelling between edge states across a quantum point contact (QPC) has already revealed rich physics, like fractionally charged excitations, or chiral Luttinger liquid. Thanks to scanning gate microscopy, we show that a single QPC can turn into an interferometer for specific potential landscapes. Spectroscopy, magnetic field and temperature dependences of electron transport reveal a quantitatively consistent interferometric behavior of the studied QPC. To explain this unexpected behavior, we put forward a new model which relies on the presence of a quantum Hall island at the centre of the constriction as well as on different tunnelling paths surrounding the island, thereby creating a new type of interferometer. This work sets the ground for new device concepts based on coherent tunnelling.
authors.affiliation: IMCN/NAPS, Université catholique de Louvain, Louvain-la-Neuve B-1348, Belgium. frederico.rodrigues@uclouvain.be
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authors.lastname: Faniel
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authors.lastname: Rosenow
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authors.lastname: Sellier
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authors.lastname: Pala
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authors.lastname: Desplanque
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authors.lastname: Wallart
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