AQP Seminar: An electron turnstile for frequency-to-power conversion
Nanometric normal-metal islands coupled to superconducting leads through insulating tunnel junctions are suitable as single-electron turnstiles when their excess charge is periodically driven by a capacitively coupled gate electrode. The superconducting leads extend the stability zone along the whole gate-voltage parameter space making it possible to create single-electron currents by only allowing one tunneling event per cycle per junction . In this device, electric charge is carried by superconducting excitations which are injected into the leads in each tunneling event. These excitations are created close to the superconducting gap edge. Consequently, the energy current, that is, power injected into the leads is given by a simple frequency to power conversion relation, namely the superconducting energy gap times the signal frequency (P=Δf). Such a simple relation enables this device as a candidate for a power standard, analogue to the frequency to the current conversion of single-electron turnstiles. This is experimentally demonstrated  as a first proof-of-concept. The power production is shown to be possible even in the absence of particle current and of little sensitivity with respect to the control parameters of the device. Moreover, the dynamics of power distribution among both junctions are studied. Further improvements in the accuracy of the device are proposed.
 Pekola, J. P. Vartiainen, J. J. Möttönen, M. Saira, O-P. Meschke, M. Averin, D. Hybrid single-electron transistor as a source of quantized electric current. Nat. Phys. 4. 2007.
 Marín-Suárez, M. Peltonen, J. T. Golubev, D. S. Pekola, J. P. An electron turnstile for frequency-to-power conversion. Nat. Nanotechnol. 2021.