BESSY II: Experimental verification of an exotic quantum phase in Au2Pb
The figure shows the measured energy-momentum relationship for Au2Pb. The linear behavior is evidence for a Dirac semimetal. In addition, a Lifshitz transition is observed: At temperatures 223 K and below, the electrons behave like positively charged particles, whereas at room temperature they behave like negatively charged ones. © HZB
A team of HZB has investigated the electronic structure of Au2Pb at BESSY II by angle-resolved photoemission spectroscopy across a wide temperature range: The results are in accordance with the electronic structure of a three-dimensional topological Dirac semimetal, in agreement with theoretical calculations.
The experimental data unveil some very special features linked to a Lifshitz transition. The study broadens the range of currently known materials exhibiting three-dimensional Dirac phases, and the observed Lifshitz transition demonstrates a viable mechanism to switch the charge carrier type in electric transport without the need for external doping. Moreover, the material becomes interesting as candidate for the realization of a topological superconductor.
The study which includes theory from San Sebastian and synthesis from Princeton was highlighted as Editor's Suggestion in the journal Physical Review Letters.
- AI-driven Catalyst Discovery: €30 million funding for German consortiumSix partners from research and industry, including Helmholtz-Zentrum Berlin (HZB), the Fritz-Haber-Institute of the Max Planck Society (FHI), BASF, Dunia Innovations, Siemens Energy, and the Technical University Berlin are launching a joint project to accelerate the catalyst discovery. The German Federal Ministry for Science, Technology and Space (BMFTR) is providing €30 million in funding for ASCEND (Accelerated Solutions for Catalysis using Emerging Nanotechnology and Digital Innovation). The research initiative targets the defossilisation of energy-intensive industries while safeguarding industrial competitiveness, with a focus on the chemical sector. The five-year project will start on 1st April 2026.
- Kick-off for a new data and AI centre in BerlinBy establishing a new data and AI centre in Berlin, the Zuse Institute Berlin (ZIB) and the Helmholtz-Zentrum Berlin (HZB) are laying the foundations for a scalable and sovereign data infrastructure in the capital. The project strengthens the scientific capabilities of Berlin’s research community whilst making an important contribution to research security, resilience and technological independence.
- Berlin Battery Lab: BAM, HZB and HU are conducting joint research on sodium batteriesThe Federal Institute for Materials Research and Testing (BAM), the Helmholtz Zentrum Berlin (HZB) and Humboldt-Universität zu Berlin (HU) today officially inaugurated the Berlin Battery Lab (BBL). At this new research platform, BAM, HZB and HU jointly develop and test resource-efficient battery technologies with a focus on sodium-based systems. Together, they develop new materials, investigate innovative cell chemistries, and produce battery prototypes. The research infrastructure of the Berlin Battery Lab is also open to external partners from science and industry and is designed to accelerate the transfer from research to application.