Scalable Parallel Single-Electron Pumps in Silicon with Split-Source Control in the Nanoampere Regime

Parallelizing single-electron pumps offers a promising route to achieving nanoampere-level currents crucial for quantum current standard applications. Achieving such current levels is essential for demonstrating the ultrahigh accuracy of single-electron pumps below 0.1 ppm toward quantum metrology triangle experiments. In addition, improving the accuracy at this current range is also desirable for practical small-current measurements. However, nanoampere-level currents have not yet been achieved with parallel pumps, mainly due to challenges in optimizing operating conditions. Here, we propose a scalable and easily implementable parallelization method based on tunable-barrier single-electron pumps with split source electrodes. By tuning the source voltages, we successfully parallelize four single-electron pumps at 200 MHz and further demonstrate a current plateau exceeding 2 nA using three pumps at 2.1 GHz. The wide applicability of this parallelization technique opens a path toward advancing high-accuracy quantum current standards.