M. Fernando Gonzalez Zalba
Hitachi Cambridge Laboratory

Energy dissipation in single-electron devices

When a single electron is non-adiabatically cycled through a charge degeneracy point additional components appear on the ac-response of single-electron devices. The resistive part, known as the Sisyphus resistance, as well as the reactive component, known as the quantum capacitance, have been studied for single-electron devices dominated by 3 dimensional density of states [1,2].
Here we present measurements on the Sisyphus effect and the quantum capacitance on a quantum object with a zero dimensional density of states, i.e. a quantum dot. The dissipative and dispersive components of a few-electron quantum dot system in silicon at frequencies comparable to the electron tunnel rates (Γ) are studied in detail. Differently from traditional radio frequency single electron transistor, the ac-excitation (f) is applied on the top gate of a silicon nanotransistor [3, 4].
The zero dimensional nature of the quantum dot modifies the electron tunnel rates which become independent of bias voltage at milikelvin temperatures. Consequently the high-frequency dissipative and dispersive response is preserved at large bias.
Additionally, we explore the dependence of the Sisyphus response with the electron tunnel rates. We demonstrate that a maximum of the resistive signal is achieved when Γ~2πf. In this case, energy dissipation is maximal.
Finally, we study the dependence of the high-frequency response with temperature and find that we can that single-electron devices at high frequencies can be used for as primary thermometers.

[1] Persson, F.. et al. Nano Letters. 10 953
[2] Cicarelli, C. et al. New J. Phys. 13 093015
[3] Gonzalez-Zalba M. F. et al Nat. Commun 6 6084
[4] Mizuta et al. Phys. Rev. B 95 045414