High-precision single-electron current source based on a silicon quantum dot

Speaker: 
Dr Tuomo Tanttu
From: 
CQC2T, UNSW
When: 
4pm Thursday 27 October 2016
Where: 
CQC2T Conference Room Level 2, Newton Building, UNSW

In addition of being extremely successful platforms for spin qubits, silicon quantum dots can be operated as robust quantized current sources. These current pumps would provide a convenient realization for the emerging quantum SI ampere, which would be based on fixed elementary charge. Here, we study silicon quantum dot charge pump that can output 80 pA current with uncertainty of less than 30 ppm and show that the pumping dot can be manipulated with external electric confinement [1]. Electron counting is performed with nearby integrated charge sensor. The counting is found to be consistent with the output current of the pump [2]. We also demonstrate pumping with three waveforms and show that it can be used to switch conveniently the pumping direction [3].
[1] A. Rossi, et al. An Accurate Single-Electron Pump Based on a Highly Tunable Silicon Quantum Dot, Nano Lett. 14, 6, (2014).
[2] T. Tanttu, et al. Electron counting in a silicon single-electron pump, New J. Phys. 17, 10, (2015).
[3] T. Tanttu, et al. Three-waveform bidirectional pumping of single electrons with a silicon quantum dot, ArXiv:1603.01225 (2016).