The electronic properties of two-dimensional magnetic topological materials (2DMTMs) are highly
susceptible to their magnetic structure. Short-ranged magnetic interactions can be fine-tuned by
small structural variations, long-range magnetic interactions that are mediated by Ruderman-
Kittel-Kasuya-Yosida (RKKY) type interactions by manipulations of the Fermi surface. Magnetic
couplings across the 2D building blocks, possibly leading to Moiré-type superstructures, change
the overall cooperative behaviour. This allows to stabilize magnetic states beyond the established
ferro- or antiferromagnetic structures, non-collinear orderings and local formation of magnetic
solitons. Spin-orbit interaction in combination with structural inversion asymmetry at magnetic
surfaces, interfaces, heterostructures, multilayers and nanostructures is a source of a variety of
spin-dependent transport phenomena and novel magnetic textures, with the chiral magnetic
skyrmions being the best known.
Recently, we established that the electronic structure in 2DMTMs depends sensitively on the
magnetization direction and is characterized by mixed topological Weyl points generating
topological magneto-electric effects. In non-collinear magnetic structures the local variation of the
electronic structure leads to electrically controllable or detectable magnetic structures of
technological potential. In addition, the vertical stacking of two-dimensional magnetic topological
materials (e.g. being in a quantum anomalous Hall state) offers the possibility to create 2D stackswith variable Chern numbers. In the last years we developed density functional theory-based tools to describe these fascinating states of matter, access their exchange interactions, determine the magnetic states at zero or finite temperature and simulate their transport properties. We expect that the application of these methods to 2D magnetic materials leads to the discovery of material classes with novel functionality and response properties.
I am grateful to my collaborators Gustav Bihlmayer, Juba Bouaziz, Markus Hoffmann, Hongying Jia, Nikolai Kiselev, Yuriy Mokrousov, Moritz Sallermann, and Mohammad Zeer for their many creative contributions.
We acknowledge funding by EU-H2020 project MAGicSky (No 665095), DARPA TEE program (#HR0011831554) from DOI, the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation program (Grant No. 856538, project “3D MAGiC”, Deutsche Forschungsgemeinschaft (DFG) through SPP 2137 “Skyrmionics” (Project No. BL 444/16), and the Collaborative Research Centers SFB 1238 (Project No. C01), as well as computing time from JARA-HPC and Jülich Supercomputing Centre.
Prof. Dr. Stefan Blügel is German citizen, Professor for Theoretical and Computational Physics at RWTH-Aachen University, Germany, and Institute Director of the Department Quantum Theory of Materials, which is part of the Peter Grünberg Institute and associate member of the Institute of Advanced Simulation, of the Forschungszentrum Jülich in Germany. He studied physics at Saarbrücken University and at RWTH-Aachen University, he carried out his research at the College of William and Mary, Williamburg, VA, USA and Forschungszentrum Jülich and
graduated (with distinction) in 1988 with a Ph.D degree in Physics at RWTH-Aachen University. He completed his Habilitation degree in 1996. Between 1988-1990 he was JSPS-postdoctoral fellow at the Institute of Solid-State Physics (ISSP) of the Tokyo University, Tokyo, Japan. Between 2001-2003 he was Associate Professor for Theoretical Physics, University of Osnabrück. He is active in several national and European science and science policy committees, is currently president of CECAM and received several national research awards. His research interest lies in quantum materials, topology, spintronics, magnetism, electronic structure theory and highperformance
computing. In the last decade he focused on spin-orbit related phenomena in quantum materials and materials system with emphasis on spinorbitronics and materials for spinorbitronics. He advocated the Dzyaloshinskii-Moriya interaction and skyrmions at surfaces and interfaces. In 2019, he received an ERC Synergy Grant (Three-dimensional magnetisation textures: Discovery and control on the nanoscale) from the European Research Council.
The electronic properties of two-dimensional magnetic topological materials (2DMTMs) are highly
susceptible to their magnetic structure. Short-ranged magnetic interactions can be fine-tuned by
small structural variations, long-range magnetic interactions that are mediated by Ruderman-
Kittel-Kasuya-Yosida (RKKY) type interactions by manipulations of the Fermi surface. Magnetic
couplings across the 2D building blocks, possibly leading to Moiré-type superstructures, change
the overall cooperative behaviour. This allows to stabilize magnetic states beyond the established
ferro- or antiferromagnetic structures, non-collinear orderings and local formation of magnetic
solitons. Spin-orbit interaction in combination with structural inversion asymmetry at magnetic
surfaces, interfaces, heterostructures, multilayers and nanostructures is a source of a variety of
spin-dependent transport phenomena and novel magnetic textures, with the chiral magnetic
skyrmions being the best known.
Recently, we established that the electronic structure in 2DMTMs depends sensitively on the
magnetization direction and is characterized by mixed topological Weyl points generating
topological magneto-electric effects. In non-collinear magnetic structures the local variation of the
electronic structure leads to electrically controllable or detectable magnetic structures of
technological potential. In addition, the vertical stacking of two-dimensional magnetic topological
materials (e.g. being in a quantum anomalous Hall state) offers the possibility to create 2D stackswith variable Chern numbers. In the last years we developed density functional theory-based tools to describe these fascinating states of matter, access their exchange interactions, determine the magnetic states at zero or finite temperature and simulate their transport properties. We expect that the application of these methods to 2D magnetic materials leads to the discovery of material classes with novel functionality and response properties.
I am grateful to my collaborators Gustav Bihlmayer, Juba Bouaziz, Markus Hoffmann, Hongying Jia, Nikolai Kiselev, Yuriy Mokrousov, Moritz Sallermann, and Mohammad Zeer for their many creative contributions.
We acknowledge funding by EU-H2020 project MAGicSky (No 665095), DARPA TEE program (#HR0011831554) from DOI, the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation program (Grant No. 856538, project “3D MAGiC”, Deutsche Forschungsgemeinschaft (DFG) through SPP 2137 “Skyrmionics” (Project No. BL 444/16), and the Collaborative Research Centers SFB 1238 (Project No. C01), as well as computing time from JARA-HPC and Jülich Supercomputing Centre.
Prof. Dr. Stefan Blügel is German citizen, Professor for Theoretical and Computational Physics at RWTH-Aachen University, Germany, and Institute Director of the Department Quantum Theory of Materials, which is part of the Peter Grünberg Institute and associate member of the Institute of Advanced Simulation, of the Forschungszentrum Jülich in Germany. He studied physics at Saarbrücken University and at RWTH-Aachen University, he carried out his research at the College of William and Mary, Williamburg, VA, USA and Forschungszentrum Jülich and
graduated (with distinction) in 1988 with a Ph.D degree in Physics at RWTH-Aachen University. He completed his Habilitation degree in 1996. Between 1988-1990 he was JSPS-postdoctoral fellow at the Institute of Solid-State Physics (ISSP) of the Tokyo University, Tokyo, Japan. Between 2001-2003 he was Associate Professor for Theoretical Physics, University of Osnabrück. He is active in several national and European science and science policy committees, is currently president of CECAM and received several national research awards. His research interest lies in quantum materials, topology, spintronics, magnetism, electronic structure theory and highperformance
computing. In the last decade he focused on spin-orbit related phenomena in quantum materials and materials system with emphasis on spinorbitronics and materials for spinorbitronics. He advocated the Dzyaloshinskii-Moriya interaction and skyrmions at surfaces and interfaces. In 2019, he received an ERC Synergy Grant (Three-dimensional magnetisation textures: Discovery and control on the nanoscale) from the European Research Council.
