Heating in electron turnstiles and pumps

Heating and therefore a loss of precision can arise easily at low temperatures in electron turnstiles and pumps based primarily on the Coulomb blockade effect. This heating is due to the fact that electrons can be deposited in excited states in the metal islands or quantum dots; the problem is exaggerated by the weakness of the relaxation processes in the islands or dots. The effects of heating can be reduced by enhancing electron-phonon coupling in the quantum dots or metal islands of such devices, or prevented by using smaller device structures where spacings between discrete levels of individual electrons are large