Universiteit Leiden

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This Week’s Discoveries | 29 January 2019

  • Ludo Juurlink
  • Kaveh Lahabi
dinsdag 29 januari 2019
Niels Bohrweg 2
2333 CA Leiden
De Sitterzaal

First Lecture

How does Pt break the H-H bond? Resolving a 4-decade old discussion

Ludo Juurlink (LIC) is an assistant professor at the Leiden Institute of Chemistry, heading the ultrahigh vacuum section of the Catalysis and Surface Chemistry group. His research focusses on gas-surface reaction dynamics and surface science with an emphasis on metal-catalyzed conversions of small molecules of interest to sustainable energy cycles.

For nearly 40 years, crucial aspects of the simplest model system in heterogeneous catalysis have been actively debated. Breaking the bond between two H-atoms on a Pt surface not only serves as a bench mark system in improving theoretical physical chemistry methods. It is also a chemical reaction central to the operation of hydrogen fuel cells and industrial chemical processes. We recently resolved a major part of the debate that may be described in terms of both chemical and physical opposing ideas. In my contribution, I will explain those ideas and how we resolved the dilemma.

Second Lecture

Magnetically controlled paths for spin-polarised supercurrents

Kaveh Lahabi (LION) is a condensed-matter physicist at Leiden. He recently completed his PhD in the group of Jan Aarts, where he currently works as a post-doc. His research implements nanostructured superconductors and magnetic hybrids to explore complex new phenomena in unconventional superconductors, correlated electron systems and superconducting spintronics

Superconductors have a unique capacity to host exotic quantum states, which can be studied and integrated in emerging technologies such as dissipationless logic circuits and quantum computing. An example of this is the phenomenon of triplet superconductivity, which refers to a superconducting state where electron pairs have a non-zero spin. While triplet superconductors are exceptionally rare in nature, under certain conditions they can also emerge at the interface between an ordinary superconductor and a ferromagnet. Realising this however has proven to be a challenging task, as it requires the presence of a specific magnetization profile at the interface. In this talk I will describe how we overcome this with the use of carefully designed magnetic hybrids, and, more importantly, how in doing so we gain new means to control the transport of superconducting currents in a device.

In particular, we show how to tailor mesoscopic pathways for supercurrents to follow in a ferromagnet. This is demonstrated in a disk-shaped device, where we utilise a ferromagnetic vortex to form two distinct transport channels in a single Josephson junction. I will conclude by demonstrating the surprising capacity of such devices in the realisation of non-volatile memory components for superconducting computing. 

Read more about the lecture series This Week's Discoveries

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