Radio frequency measurements of tunnel couplings and singlet-triplet spin states in Si:P quantum dots

M G House, T Kobayashi, B Weber, S J Hile, T F Watson, J van der Heijden, S Rogge, M Y Simmons

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49 Citations (Scopus)


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 μV 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.
Original languageEnglish
Pages (from-to)1-6
Number of pages6
JournalNature Communications
Publication statusPublished - 2015

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