This article has been reviewed according to Science X's editorial process and policies. Editors have highlighted the following attributes while ensuring the content's credibility: Fermions are among the most important particles in physics and include both everyday electrons and more exotic variants. Chiral fermions, like gloves, come in left- and right-handed versions and were proposed over a century ago.
While high-energy neutrinos—the leading candidates for massless chiral fermions—proved to have mass, nearly (semi-) metallic solid-state crystals were discovered 15 years ago to host electronic versions of massless chiral fermions. With their slightly overlapping electronic conduction and valence states, semimetals sit halfway between metals and insulators in terms of conductivity. Topological semimetals (TSMs) are distinguished by electronic properties protected by the geometric structure of their electron wavefunctions, making them resistant to disruption and exciting tabletop venues for quantum electronic responses.
Chiral TSMs come in two variants: with or without lattice structural chirality. In his postdoctoral research, Benjamin Wieder (IPhT) showed that lattice structural chirality serves as a tunable mechanism for generating ideal TSM phases. This work opened pathways for exploring industry-relevant applications, including enantioselective photoresponse (light-driven responses depending on the material's left- or right-handedness) and topologically enhanced chemical catalysis.
While theory predicted that TSM phases would be destroyed by moderate disorder, requiring highly crystalline samples, recent experiments have shown that many of the advantageous electronic properties of TSM materials persist in amorphous structural phases of the same material. To resolve this contradiction, Wieder collaborated with Adolfo Grushin's group at Université Grenoble Alpes. Using symmetry group theory methods from Wieder's ERC project TopoRosetta, the team discovered that prior studies overlooked that amorphous materials can maintain local chirality order.
Their breakthrough: local chirality order and group theory mathematics together enable the design of robust amorphous chiral TSM phases. The work is published in the journal Physical Review Materials and challenges the established view that disorder inevitably destroys metallic topological states. The team is now adapting these methods for first-principles material simulations in readily accessible amorphous materials.
Justin Schirmann et al., Geometry-enforced topological chiral fermions in amorphous chiral metals, Physical Review Materials (2026). On arXiv: arxiv.org/abs/2512.19791 Journal information: Nature Materials , arXiv Provided by The Institute of Theoretical Physics (IPhT) BSc Life Sciences & Ecology. Microbiology lab background with pharmaceutical news experience in oil, gas, and renewable industries.
Extract — continue reading at the source.
