High-resolution error detection in the capture process of a single-electron pump

• Published in: Applied physics letters 2016-01, Vol.108 (2)
• Main Authors: Giblin, S. P., See, P., Petrie, A., Janssen, T. J. B. M., Farrer, I., Griffiths, J. P., Jones, G. A. C., Ritchie, D. A., Kataoka, M.
• Format: Article
• Language: English
• Subjects: Applied physics; Beta decay; Electron capture; Electrons; Error detection; Heterostructures; Point contact; Potential barriers; Quantum dots
• ISSN: 0003-6951; 1077-3118
• DOI: 10.1063/1.4939250

The dynamic capture of electrons in a semiconductor quantum dot (QD) by raising a potential barrier is a crucial stage in metrological quantized charge pumping. In this work, we use a quantum point contact (QPC) charge sensor to study errors in the electron capture process of a QD formed in a GaAs heterostructure. Using a two-step measurement protocol to compensate for 1/f noise in the QPC current, and repeating the protocol more than 106 times, we are able to resolve errors with probabilities of order 10−6. For the studied sample, one-electron capture is affected by errors in ∼30 out of every million cycles, while two-electron capture was performed more than 106 times with only one error. For errors in one-electron capture, we detect both failure to capture an electron and capture of two electrons. Electron counting measurements are a valuable tool for investigating non-equilibrium charge capture dynamics, and necessary for validating the metrological accuracy of semiconductor electron pumps.