Berlin 2018 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 99: Poster Session: Transport

TT 99.32: Poster

Donnerstag, 15. März 2018, 15:00–19:00, Poster B

Probing the interaction of single electron pumps using RF-SETs — •David Reifert¹, Niels Ubbelohde¹, Ralf Dolata¹, Vyacheslavs Kashcheyevs², Thomas Weimann¹, and Alexander Zorin¹ — ¹Physikalisch-Technische Bundesanstalt (PTB), Bundesallee 100, 38116 Braunschweig. Germany — ²Faculty of Physics and Mathematics, University of Latvia, 25 Zellu street, LV-1002 Riga, Latvia

We utilize rf-driven semiconductor based quantum dots as single electron pumps (SEP). These SEPs transport a controlled number of n electrons per pump cycle and therefore create a precise quantized current I=n· e· f, where f is the pumping frequency. Since this current can achieve a high accuracy of 0.2 ppm, these SEPs can be utilized as a new primary standard for the unit ampere. To validate and improve the precision, we implemented an error counting scheme by operating several pumps in series and measuring the charge of the nodes in between them, with ultra-sensitive electrometers. For this purpose, we use semiconductor quantum dots, operating as single electron transistors (SET). To increase the measurement bandwidth, we applied rf-reflectometry, which allows us to read out the detector by analyzing the detuning of a LC-resonator due to the impedance change of the detector. This measurement setup enables us to investigate the transfer probabilities of the pumps operated solo or in series, and lets us test for correlations and coupling between two pumps operated in series. This allows us to examine the mechanism of the coupling between several pumps which is necessary to further improve the precision.