Transition énergétique

The driving force in materials to spontaneously form states with magnetic or electric order is of fundamental importance for basic research and device technology. The macroscopic properties and functionalities of these ferroics depend on the size, distribution and morphology of domains; that is, of regions across which such uniform order is maintained. Typically, extrinsic factors such as strain profiles, grain size or annealing procedures control the size and shape of the domains, whereas intrinsic parameters are often difficult to extract due to the complexity of a processed material. Here, we achieve this separation ...

New research has demonstrated that the secrets of the tiniest active structures in integrated circuits can be revealed using a non-destructive imaging technique. The breakthrough required the efforts of an international team of scientists from JKU and Keysight Technologies (Austria), ETH/EPFL/PSI and IBM Research - Europe (Switzerland) and from UCL (UK).

Here we investigate antiferromagnetic Eu₅In₂Sb₆, a nonsymmorphic Zintl phase. Our electrical transport data show that Eu₅In₂Sb₆ is remarkably insulating and exhibits an exceptionally large negative magnetoresistance, which is consistent with the presence of magnetic polarons. From ab initio calculations, the paramagnetic state of Eu₅In₂Sb₆ is a topologically nontrivial semimetal within the generalized gradient approximation (GGA), whereas an insulating state with trivial topological indices is obtained using a modified Becke−Johnson potential.

We use scanning tunneling microscopy to elucidate the atomically resolved electronic structure in the strongly correlated kagome Weyl antiferromagnet Mn₃Sn. In stark contrast to its broad single-particle electronic structure, we observe a pronounced resonance with a Fano line shape at the Fermi level resembling the many-body Kondo resonance. We find that this resonance does not arise from the step edges or atomic impurities but the intrinsic kagome lattice.

At the hot surface of a fuel rod cladding in the reactor water, the water is partially dissociated in hydrogen and oxygen, leading to corrosion of the cladding and to the uptake of a part of the created hydrogen. Hydrogen in solid solution and in precipitated form changes the mechanical properties of the cladding tube. The uptake of the hydrogen through the dense oxide layer is unclear. The structure and physical properties of the oxide near the metal-interface is critical The resistivity of the oxide increases with distance from the interface. Nb-containing alloys show lower resistivity in the oxide close to the metal interface, and exhibit a lower hydrogen pick-up. The time in the reactor is an important factor, leading to increasing resistivity in the oxide close to the metal interface, and a higher hydrogen uptake late in life.

Relevance of the findings: considering resistivity, the model of hydrogen uptake is better understood, revealing hints for further cladding development.

It has recently been proposed that combining chirality with topological band theory results in a totally new class of fermions. Understanding how these unconventional quasiparticles propagate and interact remains largely unexplored so far. Here, we use scanning tunneling microscopy to visualize the electronic properties of the prototypical chiral topological semimetal PdGa.

In topological materials, electrons can display behaviour that is fundamentally different from that in ‘conventional’ matter, and the magnitude of many such ‘exotic’ phenomena is directly proportional to an entity known as the Chern number. New experiments establish for the first time that the theoretically predicted maximum Chern number can be reached — and controlled — in a real material.

Moon-shot missions, such as those of Horizon Europe, require exceptional solutions, and the world-leading Analytical Research Infrastructures of Europe (ARIEs) are one of the key places those solutions can be sought. The ARIE Joint Position Paper highlighting how the common, complementary approach will help address the societal challenges of the Horizon Europe Missions framework programme was presented today.