Leading scientists on topological insulators met in Berlin
Outstanding researchers took part in the “New Trends in Topological Insulators 2014” - workshop.
From July 7-10, 150 researchers met in Berlin to discuss recent findings in the field of topological insulators.
Topological insulators are a rather new form of quantum matter with an insulating bulk and a metallic surface created by topologically protected and spin polarized electronic states.
Outstanding researchers took part in the “New Trends in Topological Insulators 2014” - workshop, organized by Gustav Bihlmayer (Forschungszentrum Jülich) and Saskia Fischer (Humboldt University and Oliver Rader of HZB. 20 speakers had been invited for presentations, the 2012 Buckley Prize winners Shoucheng Zhang and Laurens W. Molenkamp (also Leibniz Prize 2014), Zhi-Xun Shen (Buckley prize 2011) and Yoichi Ando (2014 Inoue Prize for Science) being among them.
Breakthrough results were delivered on topics such as optical excitation, electron-photon entangled states, the role of electron correlation as well as imaging of helical edge states and Majorana fermions.
The event took place on the premises of the Berlin-Brandenburg Academy of Sciences. It has been generously supported by DFG as well as HZB.
- BESSY II: How intrinsic oxygen shortens the lifespan of solid-state batteriesAlthough solid-state batteries (SSBs) demonstrate high performance and are intrinsically safe, their capacity currently declines rapidly. A team from the TU Wien, Humboldt-University Berlin and HZB has now analysed a TiS₂|Li₃YCl₆ solid-state half-cell in operando at BESSY II using a special sample environment that allows for non-destructive investigation under real operating conditions. Data obtained by combination of soft and hard X-ray photoelectron spectroscopy (XPS and HAXPES) revealed a new degradation mechanism that had not previously been identified in solid-state batteries. They have gained some surprising insights, particularly regarding the harmful role played by intrinsic oxygen. This study provides valuable information for improving design and handling of such batteries.
- Spintronics at BESSY II: Real-time analysis of magnetic bilayer systemsSpintronic devices enable data processing with significantly lower energy consumption. They are based on the interaction between ferromagnetic and antiferromagnetic layers. Now, a team from Freie Universität Berlin, HZB and Uppsala University has succeeded in tracking, for each layer separately, how the magnetic order changes after a short laser pulse has excited the system. They were also able to identify the main cause of the loss of antiferromagnetic order in the oxide layer: the excitation is transported from the hot electrons in the ferromagnetic metal to the spins in the antiferromagnet.
- Electrocatalysts: New model for charge separation at the solid-liquid interfaceHydrogen is at the heart of the transition to carbon neutrality, as both an energy carrier and a reagent for green chemistry. However, large-scale production of hydrogen via electrolysis, as well as the production of many other chemical products, requires significantly cheaper and more efficient catalysts. A precise understanding of the electrochemical processes that take place at the interface between the solid catalyst and the liquid medium is highly useful for developing better electrocatalysts. In the journal Nature Communications, an European team has now presented a powerful model that determines charge separation at the interface, the formation of the electric double layer and local electric potential variations, and the resulting influence on the catalytic activity.