News & Scientific Highlights

Krieger et al

Weyl spin-momentum locking in a chiral topological semimetal

Spin–orbit coupling in noncentrosymmetric crystals leads to spin–momentum locking – a directional relationship between an electron’s spin angular momentum and its linear momentum. Isotropic orthogonal Rashba spin–momentum locking has been studied for decades, while its counterpart, isotropic parallel Weyl spin–momentum locking has remained elusive in experiments. Theory predicts ...

Prof. Dr Milan Radovic

Neue Materialien für den Computer der Zukunft

Medienmitteilungen Forschen mit Licht Zukunftstechnologien

Forschende identifizieren und untersuchen Materialverbindungen, deren spezielle Eigenschaften neuartige Mikrochips möglich machen könnten.

PtGa highlight

Unpaired Weyl Point observed for the first time in crystalline solid

Flows need sources and sinks. That’s why, in a new class of exotic materials called Weyl semimetals, the sources and sinks of Berry curvature – dubbed Weyl points – were believed to exist only in pairs. Now researchers at PSI have observed unpaired Weyl points for the first time in a crystalline solid. This discovery, which upends conventional thinking and the so-called Nielson-Niomiya no-go theorem, demonstrates the unique properties of "nodal wall" Weyl semimetals in comparison to conventional Weyl systems having only zero-dimensional Weyl nodes.

toc fig nno

Creating novel quantum phases via the heterostructure engineering

Within this synergetic collaboration, PSI scientists have investigated the correlation between magnetic and electronic ordering in NdNiO3 by tuning its properties through proximity to a ferromagnetic manganite layer. The main outcome is that the stray magnetic field from the manganite layer causes a novel ferromagnetic-metallic (FM-M) phase in NNO. This work demonstrates the utilization of heterostructure engineering for creating novel quantum phases.

Comparison between Pr4Fe2As2Te0.88O4 and Ba(Fe1−xCox)2As2

Novel structural orthorhombicity in an iron-pnictide superconductor

Researchers from University of Zurich describe the experimental observation of a new orthorhombic structural phase in the superconducting iron-pnictide compound Pr4Fe2As2Te0.88O4. In contrast to nematicity found in underdoped iron pnictides this phase transition is not electronically driven. 

Weyl fermions

Weyl-Fermionen in einer weiteren Materialklasse entdeckt

Medienmitteilungen Zukunftstechnologien Materialforschung Forschen mit Licht

Eine besondere Art von Teilchen, sogenannte Weyl-Fermionen, waren bislang nur in bestimmten nicht-magnetischen Materialien gefunden worden. Jetzt aber haben PSI-Forschende sie erstmals auch in einem besonderen paramagnetischen Material experimentell nachgewiesen.

Type-II Weyl semimetal WP2

New study gives compelling evidence that tungsten diphosphide is a type-II Weyl semimetal

Researchers at NCCR MARVEL have combined first principles calculations with soft X-ray angle-resolved photoemission spectroscopy to examine tungsten diphosphide’s electronic structure, characterizing its Weyl nodes for the very first time. In agreement with density functional theory calculations, the results revealed two pairs of Weyl nodes lying at different binding energies. The observation of the Weyl nodes, as well as the tilted cone-like dispersions in the vicinity of the nodal points, provides compelling evidence that the material is a robust type-II Weyl semimetal with broken Lorentz invariance. This is as MARVEL researchers predicted two years ago. The research has been published in Physical Review Letters as an Editor's Suggestion.