Environmentally activated tunneling events in a hybrid single-electron box

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© 2010 American Physical Society (APS). http://www.aps.org/

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Journal Title

Journal ISSN

Volume Title

School of Science | A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä

Date

2010

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Mcode

Degree programme

Language

en

Pages

155443/1-6

Series

Physical Review B, Volume 82, Issue 15

Abstract

We have measured individual tunneling events and Coulomb step shapes in single-electron boxes with opaque superconductor–normal metal tunnel junctions. We observe anomalous broadening of the Coulomb step with decreasing temperature in a manner that is consistent with activation of first-order tunneling events by an external dissipative electromagnetic environment. We demonstrate that the rates for energetically unfavorable tunneling events saturate to finite values at low temperatures, and that the saturation level can be suppressed by more than an order of magnitude by a capacitive shunt near the device. The findings are important in assessing the performance limits of any single-electronic device. In particular, master-equation-based simulations show that the electromagnetic environment realized in the capacitively shunted devices allows for a metrologically accurate charge pump based on hybrid tunnel junctions.

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Keywords

tunneling events, Coulomb step shapes, single-electron box, superconductors, tunnel junctions

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Citation

Saira, O.-P. & Möttönen, M. & Maisi, V. F. & Pekola, Jukka. 2010. Environmentally activated tunneling events in a hybrid single-electron box. Physical Review B. Volume 82, Issue 15. 155443/1-6. ISSN 1098-0121 (printed). DOI: 10.1103/physrevb.82.155443.