Radio frequency measurements of tunnel couplings and singlet-triplet spin states in Si:P quantum dots.
Radio frequency measurements of tunnel couplings and singlet-triplet spin states in Si:P quantum dots.
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DOI：
10.1038/ncomms9848
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发表时间：
2015-11-09
影响因子：
16.6
通讯作者：
Simmons MY
中科院分区：
文献类型：
--
作者：
House MG;Kobayashi T;Weber B;Hile SJ;Watson TF;van der Heijden J;Rogge S;Simmons MY
硅中磷施主的电子和原子核的自旋态由于其优异的相干时间而成为量子信息处理应用的有力候选者。设计一台可扩展的基于施主的量子计算机将需要了解设备几何结构和电子隧道耦合之间的关系，以及使用设备中最小物理空间的自旋读出策略。在这里，我们用射频反射仪测量了一个少施主的Si：P双量子点的单重态-三重态，并证明了交换能量至少可以被调谐两个数量级，从20 μeV到8 meV。我们通过对反射信号的分析来测量点引线隧道速率，结果表明，当量子点上的电子数从1增加到4时，点引线隧道速率从100 MHz变化到22 GHz。这些技术为表征、操作和设计基于硅中施主的可扩展量子比特器件提供了一种方法。硅中的施主自旋态由于其较长的相干时间而成为很好的量子比特候选者。在这里，作者使用射频反射术测量了单态和三态，并确定了少施主硅双量子点与电引线之间的隧道耦合。
Spin states of the electrons and nuclei of phosphorus donors in silicon are strong candidates for quantum information processing applications given their excellent coherence times. Designing a scalable donor-based quantum computer will require both knowledge of the relationship between device geometry and electron tunnel couplings, and a spin readout strategy that uses minimal physical space in the device. Here we use radio frequency reflectometry to measure singlet–triplet states of a few-donor Si:P double quantum dot and demonstrate that the exchange energy can be tuned by at least two orders of magnitude, from 20 μeV to 8 meV. We measure dot–lead tunnel rates by analysis of the reflected signal and show that they change from 100 MHz to 22 GHz as the number of electrons on a quantum dot is increased from 1 to 4. These techniques present an approach for characterizing, operating and engineering scalable qubit devices based on donors in silicon. Donor spin states in silicon are good quantum bit candidates due to their long coherence times. Here, the authors use radio frequency reflectometry to measure singlet and triplet states, and to determine the tunnel coupling between few-donor silicon double quantum dots and the electrical leads.