The generation of ac modulated quantized current waveforms using a semiconductor non-adiabatic single electron pump is demonstrated. In standard operation the single electron pump generates a quantized output current of I = ef where e is the charge o
f the electron and f is the pumping frequency. Suitable frequency modulation of f allows the generation of ac modulated output currents with different characteristics. By sinusoidal and saw tooth like modulation of f accordingly modulated quantized current waveforms with kHz modulation frequencies and peak currents up to 100 pA are obtained. Such ac quantized current sources could find applications ranging from precision ac metrology to on-chip signal generation.
We study synchronized quantized charge pumping through several dynamical quantum dots (QDs) driven by a single time modulated gate signal. We show that the main obstacle for synchronization being the lack of uniformity can be overcome by operating th
e QDs in the decay cascade regime. We discuss the mechanism responsible for lifting the stringent uniformity requirements. This enhanced functionality of dynamical QDs might find applications in nanoelectronics and quantum metrology.
We operate an on-demand source of single electrons in high perpendicular magnetic fields up to 30T, corresponding to a filling factor below 1/3. The device extracts and emits single charges at a tunable energy from and to a two-dimensional electron g
as, brought into well defined integer and fractional quantum Hall (QH) states. It can therefore be used for sensitive electrical transport studies, e.g. of excitations and relaxation processes in QH edge states.
We investigate a recently developed scheme for quantized charge pumping based on single-parameter modulation. The device was realized in an AlGaAl-GaAs gated nanowire. It has been shown theoretically that non-adiabaticity is fundamentally required to
realize single-parameter pumping, while in previous multi-parameter pumping schemes it caused unwanted and less controllable currents. In this paper we demonstrate experimentally the constructive and destructive role of non-adiabaticity by analysing the pumping current over a broad frequency range.
