Violation of the Wiedemann-Franz Law in a Single-Electron Transistor

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Journal Title
Journal ISSN
Volume Title
School of Science | A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
Date
2008
Major/Subject
Mcode
Degree programme
Language
en
Pages
066801/1-4
Series
Physical Review Letters, Volume 100, Issue 6
Abstract
We study the influence of Coulomb interaction on the thermoelectric transport coefficients for a metallic single-electron transistor. By performing a perturbation expansion up to second order in the tunnel-barrier conductance, we include sequential and cotunneling processes as well as quantum fluctuations that renormalize the charging energy and the tunnel conductance. We find that Coulomb interaction leads to a strong violation of the Wiedemann-Franz law: the Lorenz ratio becomes gate-voltage dependent for sequential tunneling, and is increased by a factor 9/5 in the cotunneling regime. Finally, we suggest a measurement scheme for an experimental realization.
Description
Keywords
Coulomb interaction, thermoelectric transport coefficients, metallic single-electron transistors, tunneling
Other note
Citation
Kubala, Björn & König, Jürgen & Pekola, Jukka. 2008. Violation of the Wiedemann-Franz Law in a Single-Electron Transistor. Physical Review Letters. Volume 100, Issue 6. P. 066801/1-4. ISSN 0031-9007 (printed). DOI: 10.1103/physrevlett.100.066801.