NPL collision facilitates single-electron devices

Scientists at the National Physical Laboratory (NPL) have performed a controlled collision of single electrons in an IC. This reveals the information needed to create singleelectron devices for quantum sensing and information processing.

The experiment, described in the journal Nature Nanotechnology, examines the interaction between pairs of flying electrons as they meet in a miniature Semiconductor particle collider. Mapping the statistics of electronic collisions is a powerful approach to probing electronics interactions and the quantum properties of electrons in a given environment.NPL collision facilitates single-electron devices

Here, this technique revealed a fleetingelectrostatic ‘push’ between electrons large enough to change the electron path. This effect has not been seen in previous experiments, probably because electric field which surrounds each injected electrons is typically neutralised’ by the rearrangement of charges nearby. The Coulomb repulsion was activated here by injecting electrons into unscreened regions far from other conduction electrons.

The interaction happens on very short time scales, a few picoseconds, so the timing requirements are challenging for this experiment,” says NOL scientist Jinathan Fletcher, ‘I was really excited to see such an elementary effect, from both a physics and device engineering perspective.

While working with theorists on a model, the team realised that more subtle details present in the data can be explained by considering the microscopic behaviour of electron pairs when they are in a strong magnetic field.

The collision is not so easy to understand when the electron arrival time is slightly mismatched; the electrons repel but still follow similar trajectories,” says NPL’s Masaya Kataoka, “these effects are actually present in our model, which gives us some confidence that we understand these effects.

Harnessing Coulomb interactions between electrons will be a powerful way to control devices at high speeds and to create the non-linear effects required for quantum circuit elements based on electron quantum optics, a possible platform for quantum sensing or information processing.

Collaborators were Korea’s Advanced Institute of Science and Technology, Instituto de Fisica Interdisciplinary Sistemas ComplejosIFISC and the University of Cambridge

Research Article: Nature Nanotechnology

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