Regensburg 2016 – wissenschaftliches Programm

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DY: Fachverband Dynamik und Statistische Physik

DY 7: SKM Dissertation-Prize 2016

DY 7.2: Hauptvortrag

Montag, 7. März 2016, 10:55–11:20, H2

Self-referenced quantized current source — •Lukas Fricke — Physikalisch-Technische Bundesanstalt (PTB), Braunschweig, Germany — CQC2T, UNSW, Sydney, Australia

Scheduled for 2018, the International System of Units is about to undergo a fundamental change by introducing seven defining constants, leading to a universal system of units based on constants of nature as proposed already by Maxwell and Planck. In the case of the Ampere, the defining constant will be the elementary charge e: Employing a single-electron pump, the current I is realized by transferring a precisely known number of electrons in a clocked manner, leading to the relation I=<n> e f with <n> the average number of charge carriers transferred per cycle and f the driving clock frequency.

Here, we demonstrate a complex circuit involving serially connected electron pumps and single-electron transistors attached to the interconnecting nodes. This allows to investigate electron pumps on the level of individual transfer cycles using full counting statistics. This method enables us to derive the single-electron transfer accuracy 1−<n> of the pump and to determine the underlying mechanisms of charge transfer.

Finally, the self-referenced single-electron source is discussed which enables the in-situ verification of the output current. By counting and attributing rare transfer errors, the uncertainty of the average number of transferred electrons < n> can be reduced by orders of magnitude, thereby making a practical realization of a quantum current standard based on a clocked single-electron source feasible.