laboratoire pierre aigrain
électronique et photonique quantiques
laboratoire pierre aigrain

Seminaire, 23 Février 2015

Clemens Winkelmann (Institut Néel)
Quantized current in a single quantum level turnstile

Single electron pumps are foreseen to set the new quantum standard for
current, thereby closing the quantum metrology triangle. During the past
decade, significant experimental and theoretical effort has been spent
on the seek of quantum current generators in variety of mesoscopic
systems.We demonstrate quantized charge current in superconductor -
quantum dot - superconductor hybrid turn-stiles. The quantum dot devices
are formed by single gold nano-particles inserted in electromigrated
aluminium constrictions. Charging energies and single level spacings are
much larger than the superconducting gap, which allows charge pumping
through a single electron level. The turnstiles are operated at pumping
frequencies up to 200 MHz and reach an accuracy of 1%. We discuss the
accuracy limitation and show that the large energy level spacing
protects the device from thermally induced errors.