External field control of donor electron exchange at theSi∕SiO2interface
External field control of donor electron exchange at theSi∕SiO2interface
复制标题
Si∕SiO2界面供体电子交换的外场控制
DOI：
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发表时间：
2006
期刊：
影响因子：
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通讯作者：
S. Sarma
中科院分区：
文献类型：
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作者：
M. J. Calderón;B. Koiller;S. Sarma
我们分析了在硅量子计算机体系结构中单量子比特和双量子比特操作的几个重要问题，其中P施主靠近SiO_2界面。对于单个施主，我们研究了施主与界面之间在电场和磁场作用下的施主束缚电子操纵(即1量子比特操作)。我们建立了在没有局部表面栅的情况下在界面上保持施主束缚态的条件，并估计了避免在界面上形成二维电子气所允许的施主的最大平面密度。我们还计算了单电子在施主和界面之间穿梭的时间。对于施主对，我们发现在一定条件下，界面处各电子对之间的交换耦合(即2量子比特操作)可能与最近展示了相干自旋操纵和控制的GaAs基双电子双量子点中的耦合具有相同的数量级(例如，对于界面以下约10 nm、相距约40 nm的施主，J~10^-4 meV)，这为在Si中进行类似的实验打开了前景。
We analyze several important issues for the single- and two-qubit operations in Si quantum computer architectures involving P donors close to a SiO2 interface. For a single donor, we investigate the donor-bound electron manipulation (i.e. 1-qubit operation) between the donor and the interface by electric and magnetic fields. We establish conditions to keep a donor-bound state at the interface in the absence of local surface gates, and estimate the maximum planar density of donors allowed to avoid the formation of a 2-dimensional electron gas at the interface. We also calculate the times involved in single electron shuttling between the donor and the interface. For a donor pair, we find that under certain conditions the exchange coupling (i.e. 2-qubit operation) between the respective electron pair at the interface may be of the same order of magnitude as the coupling in GaAs-based two-electron double quantum dots where coherent spin manipulation and control has been recently demonstrated (for example for donors ~10 nm below the interface and ~40 nm apart, J~10^{-4} meV), opening the perspective for similar experiments to be performed in Si.