Imaging and controlling electron transport inside a quantum ring
Imaging and controlling electron transport inside a quantum ring
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DOI：
10.1038/nphys459
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发表时间：
2006-12-01
期刊：
影响因子：
19.6
通讯作者：
Huant, S.
中科院分区：
文献类型：
--
作者：
Hackens, B.;Martins, F.;Huant, S.
传统上，对量子输运、相干输运和弹道输运(1)的理解依赖于对宏观性质（如电导）的测量。虽然与统计理论结合起来很强大，但这种方法无法提供“电子在那里的行为”的详细图像。理想情况下，要理解纳米尺度上的传输，就需要追踪纳米器件内的每个电子。通过将扫描探针显微镜与输运测量相结合，这一目标取得了重大进展（2-7）。一些研究甚至在纳米结构环境中发现了量子输运的特征（4-6）。在这里，扫描探针显微镜被用来探测电子在开放量子环内的传播，显示出电子波干涉现象的原型：Aharonov - Bohm效应(8)。在扫描量子环上方的低温原子力显微镜的偏颇尖端时记录的电导图显示，可以原位研究相干和弹道电子的传播，甚至可以通过调整电子在纳米尺度上感受到的电位来控制。
Traditionally, the understanding of quantum transport, coherent and ballistic(1), relies on the measurement of macroscopic properties such as the conductance. Although powerful when coupled to statistical theories, this approach cannot provide a detailed image of 'how electrons behave down there'. Ideally, understanding transport at the nanoscale would require tracking each electron inside the nanodevice. Significant progress towards this goal was obtained by combining scanning probe microscopy with transport measurements(2-7). Some studies even showed signatures of quantum transport in the surroundings of nanostructures(4-6). Here, scanning probe microscopy is used to probe electron propagation inside an open quantum ring exhibiting the archetype of electron-wave interference phenomena: the Aharonov - Bohm effect(8). Conductance maps recorded while scanning the biased tip of a cryogenic atomic force microscope above the quantum ring show that the propagation of electrons, both coherent and ballistic, can be investigated in situ, and can even be controlled by tuning the potential felt by electrons at the nanoscale.