The Transregio 227 “Ultrafast Spin Dynamics” at Freie Universität Berlin investigates a special property of electrons that is responsible for the magnetism of matter — namely, electron spin — on ultrashort timescales, that is, within a few femtoseconds, the quadrillionth of a second.

This transregional Collaborative Research Center (TRR) was established in 2018 by the German Research Foundation (DFG) and has so far been funded with around 20 million euros. The DFG has now announced that it will further fund TRR 227 with an additional ten million euros from 2026 to 2029.

Fast and small – these are the requirements for future technologies and electronic devices in everyday life. Under these conditions, the electron’s spin is the most promising degree of freedom for encoding, transmitting, and processing information – potentially with low energy consumption, ultrafast speeds, and in ultrasmall volumes.

While future applications will require bandwidths in the terahertz range, the clock rates of today’s spin-based applications are two to three orders of magnitude lower. Our TRR has therefore set itself the goal of investigating spin dynamics on ultrafast timescales and atomic length scales in solids, thereby laying the foundation for new technologies. Physicists contribute their expertise from theoretical and experimental physics in the research fields of surface physics, nanoscience, materials science, magnetism, and ultrafast spectroscopy.

The spokesperson’s office of TRR 227 is located at the Department of Physics at Freie Universität Berlin, with Prof. Dr. Martin Weinelt as spokesperson. Along with the partner university, Martin Luther University Halle-Wittenberg, the Technical University of Berlin and the University of Potsdam are also involved on the university side. The non-university partners of TRR 227 in the new funding period are the Helmholtz-Zentrum Berlin, the Max Born Institute for Nonlinear Optics and Short-Pulse Spectroscopy in Berlin, and the Max Planck Institute of Microstructure Physics in Halle.

The following research groups of Freie Universität Berlin participate in TRR 227: Bolotin Lab, Brouwer, Franke, Kampfrath, Kuch, Seiler, Weinelt.

Scientific progress and the achievements of the participating researchers can be followed on the TRR's website: www.trr227.de.