Environmentally activated tunneling events in a hybrid single-electron box

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Journal Title
Journal ISSN
Volume Title
School of Science | A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
Date
2010
Major/Subject
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.
Description
Keywords
tunneling events, Coulomb step shapes, single-electron box, superconductors, tunnel junctions
Other note
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.