Related papers: Gigahertz quantized charge pumping in graphene qua…
Single-charge pumps are the main candidates for quantum-based standards of the unit ampere because they can generate accurate and quantized electric currents. In order to approach the metrological requirements in terms of both accuracy and…
In quantum metrology, semiconductor single-electron pumps are used to generate accurate electric currents with the ultimate goal of implementing the emerging quantum standard of the ampere. Pumps based on electrostatically defined tunable…
Single-electron pumps based on semiconductor quantum dots are promising candidates for the emerging quantum standard of electrical current. They can transfer discrete charges with part-per-million (ppm) precision in nanosecond time scales.…
Precise and reproducible current generation is key to realize quantum current standards in metrology. A promising candidate is a tunable-barrier single-charge pump, which can accurately transfer single charges one by one with an error rate…
Nanoscale single-electron pumps can be used to generate accurate currents, and can potentially serve to realize a new standard of electrical current based on elementary charge. Here, we use a silicon-based quantum dot with tunable tunnel…
Using standard microfabrication techniques it is now possible to construct devices, which appear to reliably manipulate electrons one at a time. These devices have potential use as building blocks in quantum computing devices, or as a…
Electron pumps generate a macroscopic electric current by controlled manipulation of single electrons. Despite intensive research towards a quantum current standard over the last 25 years, making a fast and accurate quantised electron pump…
We report on high-accuracy measurements of quantized current, sourced by a tunable-barrier single-electron pump at frequencies $f$ up to $1$ GHz. The measurements were performed with a new picoammeter instrument, traceable to the Josephson…
Electron pumps capable of delivering a current higher than 100pA with sufficient accuracy are likely to become the direct mise en pratique of the possible new quantum definition of the ampere. Furthermore, they are essential for closing the…
The remarkable electronic properties of graphene have fueled the vision of a graphene-based platform for lighter, faster and smarter electronics and computing applications. One of the challenges is to devise ways to tailor its electronic…
We propose a quantum pump mechanism based on the particular properties of graphene, namely chirality and bipolarity. The underlying physics is the excitation of evanescent modes entering a potential barrier from one lead, while those from…
We demonstrate the robust operation of a gallium arsenide tunable-barrier single-electron pump operating with 1 part-per-million accuracy at a temperature of $1.3$~K and a pumping frequency of $500$~MHz. The accuracy of current quantisation…
A well-characterised sample of silicon tunable-barrier electron pump has been operated at a frequency of 2 GHz using a custom drive waveform, generating a pump current of 320 pA. Precision measurements of the current were made as a function…
Graphene quantum dots provide promising platforms for hosting spin, valley, or spin-valley qubits. Taking advantage of the electrically generated band gap and the ambipolar nature, high-quality quantum dots can be defined in bilayer…
Quantum charge pumping, the quantum coherent generation of a dc current at zero bias through time dependent potentials, provides outstanding opportunities for metrology and the development of new devices. The long electronic coherence times…
Single-electron pumps based on tunable-barrier quantum dots are the most promising candidates for a direct realization of the unit ampere in the recently revised SI: they are simple to operate and show high precision at high operation…
We measure the average number of electrons loaded into an electrostatically-defined quantum dot (QD) operated as a tunable-barrier electron pump, using a point-contact (PC) charge sensor 1 micron away from the QD. The measurement of the…
The electrostatic confinement of massless charge carriers is hampered by Klein tunneling. Circumventing this problem in graphene mainly relies on carving out nanostructures or applying electric displacement fields to open a band gap in…
Graphene is considered to be a promising material for future electronics. The envisaged transistor applications often rely on precision cutting of graphene sheets with nanometer accuracy. In this letter we demonstrate graphene-based quantum…
Two quantized charge pumps are operated in parallel. The total current generated is shown to be far more accurate than the current produced with just one pump operating at a higher frequency. With the application of a perpendicular magnetic…