Rossi, A; Hendrickx, N W; Sammak, A; Veldhorst, M; Scappucci, G; Kataoka, M (2021) Single-hole pump in germanium. Journal of Physics D: Applied Physics, 54 (43). 434001

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Abstract

Single-charge pumps are the main candidates for the realisation of a quantum-based standard of the unit ampere because they can generate accurate and quantized electric currents. In order to approach the metrological requirements in terms of both accuracy and speed of operation, in the past decade there has been a focus on semiconductor-based devices due to their superior characteristics compared to metallic ones. Within the semiconductor space, the use of a variety of systems has retained metrological appeal to satisfy universality criteria, with gallium arsenide and silicon devices at the forefront. Here, we show that pumping can be achieved in a yet unexplored semiconductor, i.e. germanium. We realise a single-hole pump with a tunable-barrier quantum dot electrostatically defined at a Ge/SiGe heterostructure interface. We observe quantized current plateaux by driving the system with a single sinusoidal drive up to a frequency of 100 MHz. The operation of this early prototype was affected by random charge fluctuations that prevented further high-accuracy high-speed characterisation.

Item Type:	Article
Subjects:	Quantum Phenomena > Nanophysics
Divisions:	Quantum Technologies
Identification number/DOI:	10.1088/1361-6463/ac181d
Last Modified:	25 Mar 2026 15:02
URI:	https://eprintspublications.npl.co.uk/id/eprint/9421