Steele G A, Gotz G, Kouwenhoven L P
Kavli Institute of NanoScience, Delft University of Technology, Delft, The Netherlands.
Nat Nanotechnol. 2009 Jun;4(6):363-7. doi: 10.1038/nnano.2009.71. Epub 2009 Apr 6.
Quantum dots defined in carbon nanotubes are a platform for both basic scientific studies and research into new device applications. In particular, they have unique properties that make them attractive for studying the coherent properties of single-electron spins. To perform such experiments it is necessary to confine a single electron in a quantum dot with highly tunable barriers, but disorder has prevented tunable nanotube-based quantum-dot devices from reaching the single-electron regime. Here, we use local gate voltages applied to an ultraclean suspended nanotube to confine a single electron in both a single quantum dot and, for the first time, in a tunable double quantum dot. This tunability is limited by a novel type of tunnelling that is analogous to the tunnelling in the Klein paradox of relativistic quantum mechanics.
碳纳米管中定义的量子点是基础科学研究和新器件应用研究的一个平台。特别是，它们具有独特的性质，使其在研究单电子自旋的相干性质方面具有吸引力。要进行此类实验，有必要将单个电子限制在具有高度可调势垒的量子点中，但无序性阻碍了基于纳米管的可调谐量子点器件进入单电子 regime。在这里，我们使用施加到超清洁悬浮纳米管上的局部栅极电压，将单个电子限制在单个量子点中，并且首次限制在可调谐双量子点中。这种可调谐性受到一种新型隧穿的限制，这种隧穿类似于相对论量子力学的克莱因悖论中的隧穿。
