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

House, M G, Kobayashi, T, Weber, B, Hile, S J, Watson, T F, van der Heijden, J, Rogge, S and Simmons, M Y (2015) Radio frequency measurements of tunnel couplings and singlet–triplet spin states in Si:P quantum dots. Nature Communications, 6. p. 8848. ISSN 2041-1723

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Abstract

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.

Item Type: Article
Schools and Departments: School of Mathematical and Physical Sciences > Physics and Astronomy
Depositing User: Samuel Hile
Date Deposited: 15 Jan 2018 07:54
Last Modified: 15 Jan 2018 07:54
URI: http://sro.sussex.ac.uk/id/eprint/71486

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