Seminar "Pumping Single Electrons in Cape Town" by Prof. Mark Blumenthal, University of Cape Town

Titile :Pumping Single Electrons in Cape Town

Abstract
Single-electron pumps provide a powerful platform for the controlled manipulation of
individual charges and are central to both quantum metrology and emerging
quantum electronic devices. In this talk I will present recent experimental work on
single-electron pumping carried out in our nanoelectronics laboratory at the
University of Cape Town, South Africa. Our experiments focus on gate-defined
pumps in GaAs/AlGaAs heterostructures, where carefully designed split-gate
geometries allow the precise control and transport of electrons through dynamically
formed quantum dots.
I will highlight some of our latest measurements on split-gate pumps, including
studies of pump accuracy and the influence of high magnetic fields on the pumping
mechanism. These measurements provide insight into the role of Landau level
formation and confinement in stabilizing quantized current. In addition, I will briefly
discuss our developing work on controlling electrons on the surface of superfluid
helium, which offers a complementary platform for exploring highly coherent electron
systems.
Finally, I will introduce the nanoelectronics laboratory at the University of Cape Town
and describe our dilution refrigerator measurement platform, which enables low
noise measurements at millikelvin temperatures and femtoampere current levels.
Together, these capabilities allow us to explore precision charge transport and
emerging quantum electronic systems from the southern tip of Africa.

Short bio

Professor Mark Blumenthal has extensive expertise in low-dimensional nanotechnology
and electron transport at cryogenic temperatures, gained during his PhD at the
Cavendish Laboratory, Cambridge (2007), and as a Research Scientist at the UK’s
National Physical Laboratory. Since returning to South Africa in 2011, he has
established the NanoElectronics Research Group at UCT, securing funding to build a
state-of-the-art facility for low temperature semiconductor device characterization. He
lectures undergraduates and supervises a large postgraduate cohort.
His group advances high-frequency single-electron pump experiments for quantum and
metrological applications while also supporting national research in low-temperature
techniques and nanomaterial transport.