Hyperfine-induced valley mixing and the spin-valley blockade in carbon-based quantum dots
Hyperfine-induced valley mixing and the spin-valley blockade in carbon-based quantum dots
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DOI：
10.1103/physrevb.80.201404
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发表时间：
2009-11-01
影响因子：
3.7
通讯作者：
Burkard, Guido
中科院分区：
文献类型：
--
作者：
Palyi, Andras;Burkard, Guido
碳纳米管和石墨烯量子点中的超精细相互作用（HFI）是由于（13）C原子的存在。我们从理论上表明，在这些结构中，除了通常的电子自旋-核自旋耦合之外，HFI的短程性质还引起了电子的谷自由度和核自旋之间的耦合。我们预测HFI的这种性质会影响碳基双量子点的泡利阻滞输运。特别是，我们表明，只有当量子点水平的自旋和谷简并都被提升时，例如，通过适当定向的磁场，输运才会被阻挡。这种阻滞是由（1,1）电荷构型中的四个“超三重态”引起的。
Hyperfine interaction (HFI) in carbon nanotube and graphene quantum dots is due to the presence of (13)C atoms. We theoretically show that in these structures the short-range nature of the HFI gives rise to a coupling between the valley degree of freedom of the electron and the nuclear spin, in addition to the usual electron spin-nuclear spin coupling. We predict that this property of the HFI affects the Pauli blockade transport in carbon-based double quantum dots. In particular, we show that transport is blocked only if both the spin and the valley degeneracies of the quantum dot levels are lifted, e. g., by an appropriately oriented magnetic field. The blockade is caused by four "supertriplet" states in the (1,1) charge configuration.