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arXiv · 2104.01653

Asymmetric arms maximise visibility in hot-electron interferometers

Clarissa J. Barratt·Sungguen Ryu·Lewis A. Clark·H. -S. Sim·Masaya Kataoka·Clive Emary
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Abstract

We consider theoretically an electronic Mach-Zehnder interferometer constructed from quantum Hall edge channels and quantum point contacts, fed with single electrons from a dynamic quantum dot source. By considering the energy dependence of the edge-channel guide centres, we give an account of the phase averaging in this set up that is particularly relevant for the short, high-energy wavepackets injected by this type of electron source. We present both analytic and numerical results for the energy-dependent arrival time distributions of the electrons and also give an analysis of the delay times associated with the quantum point contacts and their effects on the interference patterns. A key finding is that, contrary to expectation, maximum visibility requires the interferometer arms to be different in length, with an offset of up to a micron for typical parameters. By designing interferometers that incorporate this asymmetry in their geometry, phase-averaging effects can be overcome such that visibility is only limited by other incoherent mechanisms.

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Clarissa J. Barratt, Sungguen Ryu, Lewis A. Clark, H. -S. Sim, Masaya Kataoka, Clive Emary. 2021-04-04. Asymmetric arms maximise visibility in hot-electron interferometers. https://doi.org/10.1103/physrevb.104.035436

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