© 2026 Aqora Quantum S.A.S.

Terms Privacy Legal Notice

AIP Advances

Tuning current plateau regions in parallelized single-electron pumps

Bum-Kyu Kim, Byeong-Sung Yu, Suk‐In Park, Jin Dong Song, Nam Kim, Myung‐Ho Bae

Published Oct 1, 2022• 6 citations

Abstract

The parallelization of single-electron pumps is a promising method to increase the quantized current level produced from a semiconductor-based single-electron system. In the parallelization of multiple pumps with common gate electrodes, the key process is to fabricate them with high reproducibility, resulting in an overlap of the most accurate regions in current plateaus at the same gate voltages. However, because of the lack of gating reproducibility, we here adopted a separate gate-tuning scheme to realize the overlap of the current plateaus instead of using a common gate scheme. To minimize the number of gates, we used entrance gates in common but an exit gate in separate with an additional in-common gate located outside the quantum dot but near the exit gates. The combination of the additional gate and separate exit gates led to an optimal current plateau overlap with a pair of pumps among six pumps in parallel. Under the optimal plateau-tuned condition, we achieved a relative type-A uncertainty of 1.4 × 10−6 at a 100 pA level with f = 160 MHz in the parallelized mode with the second current plateaus for both pumps.

DOI: 10.1063/5.0117055

Related papers

Hybrid single-electron turnstile - Towards a quantum standard of electric current

Jukka P Pekola, D. V. Averin, Sergey G. Kafanov +9 more

First I discuss various candidates of single-electron current pumps for quantum metrology. Then I focus on the hybrid normal-metal-superconductor turnstile in the form of a one-island single-electron transistor with one gate. The device demonstrates robust current plateaus at multiple levels of ef at frequency f. I discuss the various error mechanisms, based on our experiments and theoretical considerations. Ultimately the quantization accuracy is expected to be limited by either two-electron tunneling or by Cooper-pair-electron co-tunneling. We predict that it should be possible to achieve the metrological accuracy of 10-8, while maintaining the quantized current on the level of more than 10 pA, just by one turnstile with realistic parameters using aluminium as a superconductor. Recently we have managed to run ten turnstiles in parallel increasing the current level to above 100 pA. Work on suppressing the harmful sub-gap leakage current is in progress with encouraging experimental results.

•Jun 1, 2010•1 citation

Parallelized Single-Electron Pumps Based on Gate-Tunable Quantum Dots

Young-Seok Ghee, Ye-Hwan Ahn, Sungguen Ryu +5 more

Parallelization of pump devices is a direct way to increase the output level of the single-electron pump, which is required for metrological purposes. We fabricated a pair of single-electron pumps in parallel on a chip level and investigated their synchronized electron pumping phenomena. In the investigation, the pumping error was estimated to see whether the error was increased after the parallelization. We found that a proper choice of rf gates must be made in accordance with the direction of the applied magnetic field. In relation with the chirality of the edge state, the rf modulating gates should be chosen not to produce rf-induced heating effects.

Journal of the Korean Physical Society•Aug 1, 2019•6 citations

Robustness of single-electron pumps at sub-ppm level

Friederike Stein, Ralf Behr, Martin Götz +5 more

Single-electron pumps (SEP's) based on tunable barrier quantum dots show the most promise as high-precision nanoampere quantum sources. They are treated as a good candidate in the context of a quantum representation of the SI base unit ampere. A key point for such a realization is the robustness of operation. Here we show the invariance of current at a sub-ppm level against variation of magnetic flux density, bias voltage on source and drain and the entrance gate voltage.

Conference on Precision Electromagnetic Measurements•Jul 1, 2016•4 citations

Increasing Quantized Single-Electron Current Accuracy in a Tunable Barrier Pump by Two-Gate Modulation

Friederike Stein, Martin Götz, Thomas Weimann +3 more

Tunable barrier single-electron pumps (SEPs) have recently shown their great potential as high precision current source with direct link to the electron charge. The quantization of SEPs realized in gallium-arsenide semiconductors and driven by a single alternating control voltage routinely shows sub-ppm accuracy when applying high magnetic field. However, their accuracy without field is presently much lower. We now have found that modulation of two gates can increase accuracy in zero magnetic field and have confirmed the current quantization I=ef for a frequency of 84.5 MHz within the measurement uncertainty of less than 1 ppm.

Conference on Precision Electromagnetic Measurements•Jul 1, 2018•0 citations

Parallel quantized charge pumping

S. J. Wright, M. D. Blumenthal, M. Pepper +4 more

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 field the accuracy of quantization is shown to be $<20\text{ }\text{ppm}$ for a current of 108.9 pA. The scheme for parallel pumping presented in this work has applications in quantum information processing, the generation of single photons in pairs and bunches, neural networking, and the development of a quantum standard for electrical current. All these applications will benefit greatly from the increase in output current without the characteristic decrease in accuracy as a result of high-frequency operation.

arXiv:0906.5384•Physical Review B•Sep 16, 2009•44 citations

Gigahertz Single-Electron Pumping Mediated by Parasitic States

Alessandro Rossi, Jevgeny Klochan, Janis Timoshenko +6 more

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 quantum dots (QDs) have thus far shown the most promising performance in combining fast and accurate charge transfer. However, at frequencies exceeding approximately 1 GHz the accuracy typically decreases. Recently, hybrid pumps based on QDs coupled to trap states have led to increased transfer rates due to tighter electrostatic confinement. Here, we operate a hybrid electron pump in silicon obtained by coupling a QD to multiple parasitic states and achieve robust current quantization up to a few gigahertz. We show that the fidelity of the electron capture depends on the sequence in which the parasitic states become available for loading, resulting in distinctive frequency-dependent features in the pumped current.

arXiv:1803.00791•Nano Letters•Jun 19, 2018•14 citations

The parallelization of single-electron pumps is a promising method to increase the quantized current level produced from a semiconductor-based single-electron system. In the parallelization of multiple pumps with common gate electrodes, the key process is to fabricate them with high reproducibility, resulting in an overlap of the most accurate regions in current plateaus at the same gate voltages. However, because of the lack of gating reproducibility, we here adopted a separate gate-tuning scheme to realize the overlap of the current plateaus instead of using a common gate scheme. To minimize the number of gates, we used entrance gates in common but an exit gate in separate with an additional in-common gate located outside the quantum dot but near the exit gates. The combination of the additional gate and separate exit gates led to an optimal current plateau overlap with a pair of pumps among six pumps in parallel. Under the optimal plateau-tuned condition, we achieved a relative type-A uncertainty of 1.4 × 10−6 at a 100 pA level with f = 160 MHz in the parallelized mode with the second current plateaus for both pumps.

First I discuss various candidates of single-electron current pumps for quantum metrology. Then I focus on the hybrid normal-metal-superconductor turnstile in the form of a one-island single-electron transistor with one gate. The device demonstrates robust current plateaus at multiple levels of ef at frequency f. I discuss the various error mechanisms, based on our experiments and theoretical considerations. Ultimately the quantization accuracy is expected to be limited by either two-electron tunneling or by Cooper-pair-electron co-tunneling. We predict that it should be possible to achieve the metrological accuracy of 10-8, while maintaining the quantized current on the level of more than 10 pA, just by one turnstile with realistic parameters using aluminium as a superconductor. Recently we have managed to run ten turnstiles in parallel increasing the current level to above 100 pA. Work on suppressing the harmful sub-gap leakage current is in progress with encouraging experimental results.

Parallelization of pump devices is a direct way to increase the output level of the single-electron pump, which is required for metrological purposes. We fabricated a pair of single-electron pumps in parallel on a chip level and investigated their synchronized electron pumping phenomena. In the investigation, the pumping error was estimated to see whether the error was increased after the parallelization. We found that a proper choice of rf gates must be made in accordance with the direction of the applied magnetic field. In relation with the chirality of the edge state, the rf modulating gates should be chosen not to produce rf-induced heating effects.

Tunable barrier single-electron pumps (SEPs) have recently shown their great potential as high precision current source with direct link to the electron charge. The quantization of SEPs realized in gallium-arsenide semiconductors and driven by a single alternating control voltage routinely shows sub-ppm accuracy when applying high magnetic field. However, their accuracy without field is presently much lower. We now have found that modulation of two gates can increase accuracy in zero magnetic field and have confirmed the current quantization I=ef for a frequency of 84.5 MHz within the measurement uncertainty of less than 1 ppm.

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 field the accuracy of quantization is shown to be

<20\text{ }\text{ppm}

for a current of 108.9 pA. The scheme for parallel pumping presented in this work has applications in quantum information processing, the generation of single photons in pairs and bunches, neural networking, and the development of a quantum standard for electrical current. All these applications will benefit greatly from the increase in output current without the characteristic decrease in accuracy as a result of high-frequency operation.

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 quantum dots (QDs) have thus far shown the most promising performance in combining fast and accurate charge transfer. However, at frequencies exceeding approximately 1 GHz the accuracy typically decreases. Recently, hybrid pumps based on QDs coupled to trap states have led to increased transfer rates due to tighter electrostatic confinement. Here, we operate a hybrid electron pump in silicon obtained by coupling a QD to multiple parasitic states and achieve robust current quantization up to a few gigahertz. We show that the fidelity of the electron capture depends on the sequence in which the parasitic states become available for loading, resulting in distinctive frequency-dependent features in the pumped current.