Department of Physics, Virginia Tech, Blacksburg, VA 24061, USA.
J Phys Condens Matter. 2013 Oct 30;25(43):435301. doi: 10.1088/0953-8984/25/43/435301. Epub 2013 Oct 4.
Low-temperature Aharonov-Bohm oscillations in the magnetoresistance of mesoscopic interferometric rings patterned on an InGaAs/InAlAs heterostructure are investigated for their dependence on excitation current and temperature. The rings have an average radius of 650 nm, and a lithographic arm width of 300 nm, yielding pronounced interference oscillations over a wide range of magnetic fields. Apart from a current and temperature dependence, the oscillation amplitude also shows a quasi-periodic modulation with applied magnetic field. The phase coherence length is extracted by analysis of the fundamental and higher Fourier components of the oscillations, and by direct analysis of the amplitude and its dependence on parameters. It is concluded that the Thouless energy forms the measure of excitation energies for quantum decoherence. The amplitude modulation finds an explanation in the effect of the magnetic flux threading the finite width of the interferometer arms.
低温下的 Aharonov-Bohm 干涉在介观干涉环的磁阻中的振荡，研究了它们对激励电流和温度的依赖性。这些环的平均半径为 650nm，光刻臂的宽度为 300nm，在很宽的磁场范围内产生明显的干涉振荡。除了电流和温度的依赖性外，振荡幅度也表现出与外加磁场的准周期性调制。通过对振荡的基本和更高阶傅里叶分量的分析，以及对振幅及其对参数的依赖性的直接分析，提取了相位相干长度。得出结论，Thouless 能量构成了量子退相干激励能量的量度。振幅调制的解释在于磁通贯穿干涉仪臂有限宽度的效应。
