© 2026 Aqora Quantum S.A.S.

Terms Privacy Legal Notice

Scientific Reports

High-accuracy current generation in the nanoampere regime from a silicon single-trap electron pump

Gento Yamahata, S. P. Giblin, M. Kataoka, T. Karasawa, Akira Fujiwara

Published Mar 21, 2017• 42 citations

Abstract

A gigahertz single-electron (SE) pump with a semiconductor charge island is promising for a future quantum current standard. However, high-accuracy current in the nanoampere regime is still difficult to achieve because the performance of SE pumps tends to degrade significantly at frequencies exceeding 1 GHz. Here, we demonstrate robust SE pumping via a single-trap level in silicon up to 7.4 GHz, at which the pumping current exceeds 1 nA. An accuracy test with an uncertainty of about one part per million (ppm) reveals that the pumping current deviates from the ideal value by only about 20 ppm at the flattest part of the current plateau. This value is two orders of magnitude better than the best one reported in the nanoampere regime. In addition, the pumping accuracy is almost unchanged up to 7.4 GHz, probably due to strong electron confinement in the trap. These results indicate that trap-mediated SE pumping is promising for achieving the practical operation of the quantum current standard.

DOI: 10.1038/srep45137

Related papers

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

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

Thermal-Error Regime in High-Accuracy Gigahertz Single-Electron Pumping

Ruichen Zhao, Alessandro Rossi, S. P. Giblin +5 more

Single-electron pumps based on quantum dots (QDs) with tunable barriers are promising candidates for the emerging quantum standard of electrical current, but accuracy at elevated reservoir temperatures can be challenging. In this study, a planar silicon QD achieves accurate, high-speed single-electron pumping in the thermal regime, where reservoir temperature could rise to a few kelvin. This device operates without the demanding conditions of previous experiments, indicating that it could deliver a cost-effective and easily distributed standard of current---and, furthermore, could be useful for long-range transfer of quantum information.

arXiv:1703.04795•Physical Review Applied•Oct 30, 2017•47 citations

Gigahertz single-hole transfer in Si tunable-barrier pumps

Gento Yamahata, T. Karasawa, Akira Fujiwara

We report high-speed single-hole (SH) transfer using Si tunable-barrier pumps comprising p-type metal-oxide-semiconductor field-effect transistors. A clear SH-transfer-current plateau with the current level of about 160 pA was observed when a clock signal having a frequency of 1 GHz was applied to one of the gates. Temperature dependence measurements of the transfer current reveal that the transfer probability is dominated by non-equilibrium SH escape by thermal hopping from the electrically formed charge island. The lower bound of the relative error rate for the 1-GHz transfer is about 10−3 at a temperature of about 17 K. In addition, we investigate the frequency dependence of the transfer, where we discuss possible sources causing the change in the error rate. These results pave the way for accurate manipulation of SHs and its application to metrological current standards.

Applied Physics Letters•Jan 12, 2015•19 citations

Three-waveform bidirectional pumping of single electrons with a silicon quantum dot

Tuomo Tanttu, Alessandro Rossi, Kuan Yen Tan +4 more

Semiconductor-based quantum dot single-electron pumps are currently the most promising candidates for the direct realization of the emerging quantum standard of the ampere in the International System of Units. Here, we discuss a silicon quantum dot single-electron pump with radio frequency control over the transparencies of entrance and exit barriers as well as the dot potential. We show that our driving protocol leads to robust bidirectional pumping: one can conveniently reverse the direction of the quantized current by changing only the phase shift of one driving waveform with respect to the others. We anticipate that this pumping technique may be used in the future to perform error counting experiments by pumping the electrons into and out of a reservoir island monitored by a charge sensor.

arXiv:1603.01225•Scientific Reports•Nov 8, 2016•11 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

A gigahertz single-electron (SE) pump with a semiconductor charge island is promising for a future quantum current standard. However, high-accuracy current in the nanoampere regime is still difficult to achieve because the performance of SE pumps tends to degrade significantly at frequencies exceeding 1 GHz. Here, we demonstrate robust SE pumping via a single-trap level in silicon up to 7.4 GHz, at which the pumping current exceeds 1 nA. An accuracy test with an uncertainty of about one part per million (ppm) reveals that the pumping current deviates from the ideal value by only about 20 ppm at the flattest part of the current plateau. This value is two orders of magnitude better than the best one reported in the nanoampere regime. In addition, the pumping accuracy is almost unchanged up to 7.4 GHz, probably due to strong electron confinement in the trap. These results indicate that trap-mediated SE pumping is promising for achieving the practical operation of the quantum current standard.

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.

Single-electron pumps based on quantum dots (QDs) with tunable barriers are promising candidates for the emerging quantum standard of electrical current, but accuracy at elevated reservoir temperatures can be challenging. In this study, a planar silicon QD achieves accurate, high-speed single-electron pumping in the thermal regime, where reservoir temperature could rise to a few kelvin. This device operates without the demanding conditions of previous experiments, indicating that it could deliver a cost-effective and easily distributed standard of current---and, furthermore, could be useful for long-range transfer of quantum information.

We report high-speed single-hole (SH) transfer using Si tunable-barrier pumps comprising p-type metal-oxide-semiconductor field-effect transistors. A clear SH-transfer-current plateau with the current level of about 160 pA was observed when a clock signal having a frequency of 1 GHz was applied to one of the gates. Temperature dependence measurements of the transfer current reveal that the transfer probability is dominated by non-equilibrium SH escape by thermal hopping from the electrically formed charge island. The lower bound of the relative error rate for the 1-GHz transfer is about 10−3 at a temperature of about 17 K. In addition, we investigate the frequency dependence of the transfer, where we discuss possible sources causing the change in the error rate. These results pave the way for accurate manipulation of SHs and its application to metrological current standards.

Semiconductor-based quantum dot single-electron pumps are currently the most promising candidates for the direct realization of the emerging quantum standard of the ampere in the International System of Units. Here, we discuss a silicon quantum dot single-electron pump with radio frequency control over the transparencies of entrance and exit barriers as well as the dot potential. We show that our driving protocol leads to robust bidirectional pumping: one can conveniently reverse the direction of the quantized current by changing only the phase shift of one driving waveform with respect to the others. We anticipate that this pumping technique may be used in the future to perform error counting experiments by pumping the electrons into and out of a reservoir island monitored by a charge sensor.

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.