Phase shifts and phase π jumps in four-terminal waveguide Aharonov-Bohm interferometers
Phase shifts and phase π jumps in four-terminal waveguide Aharonov-Bohm interferometers
复制标题
四端波导阿哈罗诺夫-玻姆干涉仪中的相移和相位 π 跳变
DOI：
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发表时间：
2010
期刊：
影响因子：
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通讯作者：
A. Wieck
中科院分区：
文献类型：
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作者：
C. Kreisbeck;Tobias Kramer;Sven S. Buchholz;S. F. Fischer;U. Kunze;D. Reuter;A. Wieck
在Aharonov-Bohm （AB）干涉仪中可以研究电子的量子相干特性。本文从实验和理论两方面研究了四端准一维AlGaAs/ gaas波导AB环的传输相位演化。作为除磁场外的主要控制参数，我们使用顶栅沿路径调谐费米波数。我们的实验结果和理论计算表明，测量配置对四端器件的ab -电阻振荡相位有很强的影响。当非局部设置显示AB振荡的连续相移时，在局部电压探针设置中相位保持刚性。在所有的测量配置中都发现了突然的相位跳变。我们分析了相移作为磁场和费米能量的函数，并给出了该装置的详细理论模型。环臂上的散射和反射是突变相位跳变的来源。
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 nonlocal 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 $ensuremath{pi}$.