Role of interactions in an electronic Fabry-Perot interferometer operating in the quantum Hall effect regime
Role of interactions in an electronic Fabry-Perot interferometer operating in the quantum Hall effect regime
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DOI：
10.1073/pnas.0912624107
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发表时间：
2010-03-23
影响因子：
11.1
通讯作者：
Mahalu, Diana
中科院分区：
文献类型：
--
作者：
Ofek, Nissim;Bid, Aveek;Mahalu, Diana
边缘通道干涉有望成为研究量子霍尔效应中带电准粒子统计的重要工具。本文详细研究了一种工作在QHE区的电子法布里-珀罗干涉仪（FPI）[C。Chamon等人（1997）Phys Rev B 55：2331-2334]，其中干扰准粒子的相位由Aharonov-Bohm效应控制。我们的主要发现是，电子之间的库仑相互作用占主导地位的干扰，即使在一个相对较大的面积FPI，导致磁场上的干扰环所包围的区域的强烈依赖性。特别是，对于复合边缘结构，与几个独立的边缘通道传播沿着的边缘，干扰的最外边缘通道（属于最低的朗道水平）是不敏感的磁场，这表明一个恒定的封闭通量。然而，当任何一个内边缘通道干扰时，当磁场增加时，封闭的通量减小。通过有意地改变具有偏置金属栅极的封闭区域并观察干涉图案的周期性，发现电荷e（对于整数填充因子）和e/3（对于分数填充因子）从FPI排出。此外，这些观测也提供了一种新的方法来检测干扰准粒子的电荷。
Interference of edge channels is expected to be a prominent tool for studying statistics of charged quasiparticles in the quantum Hall effect (QHE). We present here a detailed study of an electronic Fabry-Perot interferometer (FPI) operating in the QHE regime [C. Chamon, et al. (1997) Phys Rev B 55: 2331-2334], with the phase of the interfering quasiparticles controlled by the Aharonov-Bohm effect. Our main finding is that Coulomb interactions among the electrons dominate the interference, even in a relatively large area FPI, leading to a strong dependence of the area enclosed by the interference loop on the magnetic field. In particular, for a composite edge structure, with a few independent edge channels propagating along the edge, interference of the outmost edge channel (belonging to the lowest Landau level) was insensitive to magnetic field-suggesting a constant enclosed flux. However, when any of the inner edge channels interfered, the enclosed flux decreased when the magnetic field increased. By intentionally varying the enclosed area with a biased metallic gate and observing the periodicity of the interference pattern, charges e (for integer filling factors) and e/3 (for a fractional filling factor) were found to be expelled from the FPI. Moreover, these observations provided also a novel way of detecting the charge of the interfering quasiparticles.