Non-equilibrium edge-channel spectroscopy in the integer quantum Hall regime
Non-equilibrium edge-channel spectroscopy in the integer quantum Hall regime
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DOI：
10.1038/nphys1429
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发表时间：
2010-01-01
期刊：
影响因子：
19.6
通讯作者：
Pierre, F.
中科院分区：
文献类型：
--
作者：
Altimiras, C.;le Sueur, H.;Pierre, F.
热输运的研究有可能揭示介观系统物理学的新见解。对于那些显示整数量子霍尔效应(1)的研究尤其如此，其中霍尔电流的鲁棒量子化限制了仅从电荷输运中获得的信息量(2)。因此，我们对这些系统中无间隙边缘激励的理解是不完整的。有效边态理论将它们描述为典型的一维手性费米子（3,4）——一幅简单的图片，解释了大量的观测结果(5)，并建议使用量子点接触作为电子束分离器来探索各种量子力学现象（6-8）。然而，这幅图显然与主流理论框架不一致，后者预测在大多数情况下(9)额外的无间隙边缘模式（10）。在这里，我们提出了一种光谱技术，通过探测非平衡边缘通道中的分布函数和能量流，解决了注入能量是否被预测的额外状态捕获的问题。我们的结果表明，情况并非如此，因此，对于能量传输，量子点接触确实表现为光束分离器。这为热传递和非平衡实验提供了一个有用的新工具。
The study of heat transport has the potential to reveal new insights into the physics of mesoscopic systems. This is especially true of those that show the integer quantum Hall effect(1), in which the robust quantization of Hall currents limits the amount of information that can be obtained from charge transport alone(2). As a consequence, our understanding of gapless edge excitations in these systems is incomplete. Effective edge-state theory describes them as prototypical one-dimensional chiral fermions(3,4)-a simple picture that explains a large body of observations(5) and suggests the use of quantum point contacts as electronic beam splitters to explore a variety of quantum mechanical phenomena(6-8). However, this picture is in apparent disagreement with the prevailing theoretical framework, which predicts in most situations(9) extra gapless edge modes(10). Here, we present a spectroscopic technique that addresses the question of whether some of the injected energy is captured by the predicted extra states, by probing the distribution function and energy flow in an edge channel operated out-of-equilibrium. Our results show it is not the case and therefore that regarding energy transport, quantum point contacts do indeed behave as optical beam splitters. This demonstrates a useful new tool for heat transport and out-of-equilibrium experiments.