Kondo physics in carbon nanotubes
Kondo physics in carbon nanotubes
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DOI：
10.1038/35042545
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发表时间：
2000-11-16
期刊：
影响因子：
64.8
通讯作者：
Lindelof, PE
中科院分区：
文献类型：
--
作者：
Nygård, J;Cobden, DH;Lindelof, PE
电导与线状分子的连接是分子电子学发展的合乎逻辑的一步，但也使基础物理学的研究成为可能。例如，金属碳纳米管(1)是已经被发现作为一维量子点(2，3)、Luttinger液体(4，5)、邻近感应超导体(6，7)和弹道(8)和扩散(9)一维金属的量子线。在这里，我们报道了电接触的单壁碳纳米管可以作为近藤物理的强大探测器，证明了近藤效应的普遍性。在典型情况下，由于局域杂质磁矩和金属主体中非局域电子之间的相互作用，近藤效应被用来解释(10)金属中磁性杂质的低温增强散射，并在通过半导体量子点的输运中发生(11-18)。与原子杂质相比，点(在我们的例子中是纳米管)的可调性要强得多，这使得新的类近藤效应(19，20)变得容易获得。我们的纳米管设备与以前观察到近藤效应的系统不同，因为它们是带有三维金属(金)储存库的一维量子点。这使我们能够观察到近藤共振非常大的电子数(N)在点，并接近么正极限(其中传输达到其最大可能的值)。此外，我们还检测到了以前未观察到的近藤效应，该效应发生在磁场中N的偶数值上。
The connection of electrical leads to wire-like molecules is a logical step in the development of molecular electronics, but also allows studies of fundamental physics. For example, metallic carbon nanotubes(1) are quantum wires that have been found to act as one-dimensional quantum dots(2,3), Luttinger liquids(4,5), proximity-induced superconductors(6,7) and ballistic(8) and diffusive(9) one-dimensional metals. Here we report that electrically contacted single-walled carbon nanotubes can serve as powerful probes of Kondo physics, demonstrating the universality of the Kondo effect. Arising in the prototypical case from the interaction between a localized impurity magnetic moment and delocalized electrons in a metallic host, the Kondo effect has been used to explain(10) enhanced low-temperature scattering from magnetic impurities in metals, and also occurs in transport through semiconductor quantum dots(11-18). The far greater tunability of dots (in our case, nanotubes) compared with atomic impurities renders new classes of Kondo-like effects(19,20) accessible. Our nanotube devices differ from previous systems in which Kondo effects have been observed, in that they are one-dimensional quantum dots with three-dimensional metal (gold) reservoirs. This allows us to observe Kondo resonances for very large electron numbers (N) in the dot, and approaching the unitary limit (where the transmission reaches its maximum possible value). Moreover, we detect a previously unobserved Kondo effect, occurring for even values of N in a magnetic field.