Electric-field tuning of the valley splitting in silicon corner dots

D. J. Ibberson, L. Bourdet, J. C. Abadillo-Uriel, I. Ahmed, S. Barraud, M. J. Calderón, Y. M. Niquet, M. F. Gonzalez-Zalba

Research output: Contribution to journalLetter (Academic Journal)peer-review

11 Citations (Scopus)
210 Downloads (Pure)

Abstract

We perform an excited state spectroscopy analysis of a silicon corner dot in a nanowire field-effect transistor to assess the electric field tunability of the valley splitting. First, we demonstrate a back-gate-controlled transition between a single quantum dot and a double quantum dot in parallel which allows tuning the device into corner dot formation. We find a linear dependence of the valley splitting on back-gate voltage, from 880 μeV to 610 μeV with a slope of −45 ± 3 μeV/V (or equivalently a slope of −48 ± 3 μeV/(MV/m) with respect to the effective field). The experimental results are backed up by tight-binding simulations that include the effect of surface roughness, remote charges in the gate stack, and discrete dopants in the channel. Our results demonstrate a way to electrically tune the valley splitting in silicon-on-insulator-based quantum dots, a requirement to achieve all-electrical manipulation of silicon spin qubits.
Original languageEnglish
Article number053104
Number of pages5
JournalApplied Physics Letters
Volume113
Issue number5
Early online date1 Aug 2018
DOIs
Publication statusPublished - 2018

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