Upstream modes and antidots poison graphene quantum Hall effect

A collaboration between the groups of Benoit Hackens at UC Louvain and of Christoph Stampfer at RWTH Aachen University solves the puzzle of the fragility of the quantum Hall effect in graphene.

The quantum Hall effect is both a textbook example of topological protection and a central tool of metrology labs. In graphene, the quantum Hall effect can be observed at much higher temperatures than in high mobility semiconductors, but the topological protection turned out to be regrettably less robust.

Using scanning gate microscopy on samples fabricated in the lab of Christoph Stampfer, the team of Benoit Hackens has now been able to pinpoint the cause of the vulnerability of the graphene quantum Hall channels. The results clearly indicate the detrimental role of antidots along the graphene edges and provide insights on how to counteract their influence.  

A nice popular account of the work published by UCLouvain can be read here.

Article reference:
Upstream modes and antidots poison graphene quantum Hall effect
N. Moreau, B. Brun, S. Somanchi, , K. Watanabe, T. Taniguchi, C. Stampfer & B. Hackens
Nature Communications 12, 4265 (2021).
https://doi.org/10.1038/s41467-021-24481-2

What should the future look like? – An interview with Max Lemme over the Future-Cluster NeuroSys

In a video interview for the Faculty of Electrical Engineering and Information Technology of RWTH Aachen University, Prof. Max Lemme explains the vision behind the Future-Cluster NeuroSys, the role of neuromorphic hardware in shaping the future of artificial intelligence applications, and the necessity of addressing not only the technical aspects, but also the socio-economic implications of this new technology, to ensure that it conforms “by design” with European values.

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A scalable method for the large-area integration of 2D materials

Two-dimensional (2D) materials have a huge potential for providing devices with much smaller size and extended functionalities with respect to what can be achieved with today’s silicon technologies. But to exploit this potential we must be able to integrate 2D materials into semiconductor manufacturing lines – a notoriously difficult step. A team of researchers from Sweden and Germany now reports a new method to make this work. 

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