New instrument at BESSY II commences user operation

A new instrument became available to the users of BESSY II on Oct. 28, 2019. The new beamline and apparatus for spin- and angular-resolved photoemission in the Russian-German Laboratory at BESSY II have successfully completed their test phase. They facilitate precise measurements of the electron band structure and spin of different material classes such as topological insulators and magnetic sandwich structures, as well as novel perovskite-based solar-cell materials. A photoelectron microscope has also been developed which is particularly important for nanoscopic structures.

The Russian-German Laboratory has existed at BESSY II for more than fifteen years, operating its own beamline for absorption and photoelectron spectroscopy. Now, in addition to the dipole beamline, lab members have also set up a powerful measurement station for spin- and angularly-resolved photoelectron spectroscopy and photoelectron microscopy on an undulator beamline. This measurement station was developed together with Technische Universität Dresden (TU Dresden) and Freie Universität Berlin through a German Federal Ministry of Education and Research (BMBF) grant. The measurement station along with Russian and German user-support teams will be available beginning at the next beamtime period.

International Workshop

Prof. Eckart Rühl of Freie Universität Berlin, chairman of the laboratory's steering committee, emphasises the strong ties with Russian colleagues. “In order to familiarise Russian research groups with the new opportunities offered by the instrument, we have launched the instrument as part of an international workshop”, explains Rühl. 26 researchers (seven women and nineteen men) from Russia, Germany, Spain, and Japan will report on their experiments over the two-day event.

Measuring spin-orbit interactions

“In recent years, spin-orbit interactions, i.e. the coupling of magnetic orientation to the direction of motion of electrons, has developed without pause to become a main research topic in solid-state physics. This was particularly due to the discovery of a new class of materials called topological insulators, which was honoured by the 2016 Nobel Prize in Physics“, explains Prof. Oliver Rader of the HZB, in whose department the new instrument is located. “This led to a sharp increase in international demand for experiments that can detect spin directly.” The current interest in stable two-dimensional solids might also contribute to this demand as well, for novel two-dimensional magnets such as CrI₃ have been discovered in recent years.

Reception at the Russian Embassy

The great importance attached to the laboratory was exemplified by the participation of the Embassy of the Russian Federation: Alexander Rusinov, attaché for the Department of Education, Science, and Technology at the Embassy, gave the opening address, and the Federation Ambassador received the participants in the evening.

Partners of the collaboration:

The collaboration is being supported by Freie Universität Berlin, TU Dresden, TU Freiberg, and the Helmholtz-Zentrum Berlin on the German side, while from the Russian side by St. Petersburg State Univerisity, the Kurchatov Institute (Moscow), Ioffe Physical-Technical Institute of the Russian Academy of Sciences (Ioffe Institute, St. Petersburg), and the Shubnikov Institute of Crystallography (Moscow).