Spin coherence, spin qubits, and spin transport in carbon nanostructures

该理论项目涉及碳基纳米结构中的自旋相干性和磁相互作用，如量子点（QD），纳米片，纳米带（GNR）和碳纳米管（CNT）以及扩展的石墨烯。我们主要研究了：（1）量子点和纳米片中局域电子的自旋性质，这些电子的自旋性质可以与移动的自旋性质有很大的不同。基于准1D材料（GNRs、CNT）的QD中的自旋物理预计不同于2D结构。(2)石墨烯中移动的电子的自旋相干性和弛豫已经在实验上进行了研究[1]，但是在这一点上还没有理解它们的各向异性等几个方面。进一步的动力来自于作为量子位的潜在用途，其中相干性至关重要。碳是一种非常规但有前途的自旋量子比特和其他自旋电子学应用材料。与III-V族半导体相比，碳中的自旋轨道耦合较弱，允许长的自旋弛豫时间T1。碳也具有非常稀的核自旋，允许长的自旋相干时间T2。我们建议继续一个现有项目（第一个供资期的结果，见下文）。该项目的主题没有改变，但有以下重要调整：（1）该项目被延长，现在由两名主要研究者（C。亚琛工业大学的Honerkamp申请加入研究单位）。(2)该项目更侧重于材料方面，因为我们现在专注于碳，我们在第一个融资期取得了最好的结果，这与其他项目的重组一致。

This theory project deals with spin coherence and magnetic interactions in carbon- based nanostructures such as quantum dots (QDs), nanoflakes, nanoribbons (GNRs), and carbon nanotubes (CNTs), as well as extended graphene. We focus on: (1) Spin properties of localized electrons in QDs and nanoflakes which can deviate substantially from that of mobile spins. Spin physics in QDs based on quasi-1D materials (GNRs, CNTs) are expected to be different from 2D structures. (2) Spin coherence and relaxation of mobile electrons in graphene have been studied experimentally [1], but several aspects such as their anisotropy are not understood at this point. Further motivation comes from the potential use as qubits where coherence is essential. Carbon is an unconventional but promising material for spin qubits and other spintronics applications. In contrast to III-V semiconductors, spin-orbit coupling in carbon is weak, allowing for long spin relaxartion times T1. Carbon also has very dilute nuclear spins, allowing for long spin coherence times T2. We propose to continue an existing project (results from the first funding period, see below). The topic of the project is unchanged, with these important adjustments: (1) The project is extended and now lead by two principal investigators (C. Honerkamp of RWTH Aachen applies to join the Research Unit). (2) The project is more focused in terms of materials, as we now concentrate on carbon where we have achieved the best results in the first funding period and which is in line with the regrouping of the other projects.