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arXiv · 1007.3439

Phase shifts and phase $π$-jumps in four-terminal waveguide Aharonov-Bohm interferometers

Christoph Kreisbeck·Tobias Kramer·Sven S. Buchholz·Saskia F. Fischer·Ulrich Kunze·Dirk Reuter·Andreas D. Wieck
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Abstract

Quantum coherent properties of electrons can be studied in Aharonov-Bohm (AB) interferometers. We investigate both experimentally and theoretically the transmission phase evolution in a four-terminal quasi-one-dimensional AlGaAs/GaAs-based waveguide AB ring. As main control parameter besides the magnetic field, we tune the Fermi wave number along the pathways using a top-gate. Our experimental results and theoretical calculations demonstrate the strong influence of the measurement configuration upon the AB-resistance-oscillation phase in a four-terminal device. While the non-local setup displays continuous phase shifts of the AB oscillations, the phase remains rigid in the local voltage-probe setup. Abrupt phase jumps are found in all measurement configurations. We analyze the phase shifts as functions of the magnetic field and the Fermi energy and provide a detailed theoretical model of the device. Scattering and reflections in the arms of the ring are the source of abrupt phase jumps by $π$.

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Christoph Kreisbeck, Tobias Kramer, Sven S. Buchholz, Saskia F. Fischer, Ulrich Kunze, Dirk Reuter, Andreas D. Wieck. 2010-07-22. Phase shifts and phase $π$-jumps in four-terminal waveguide Aharonov-Bohm interferometers. https://doi.org/10.1103/physrevb.82.165329

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