In the past years, the advent of geometrical, or Berry phases, in condensed matter physics caused a mini-revolution in the field of transport and dynamical properties of electronic and spin systems exposed to external magnetic and electric fields. Topological concepts caused a paradigm shift in modern electronics since they manifest themselves in a manifold of novel observed and predicted effects and properties of real materials, such as dissipationless spin currents or the appearance of topologically non-trivial states of matter.
Our group is dedicated to exploring the appearance of and ways of utilizing the geometrical concepts and phenomena related to geometrical phases in the solid state for use in future nanoelectronics.
As a group, we focus on novel response and transport effects in complex magnetic systems ranging from interfaces of transition metals to skyrmions. We make extensive use of the predictive power of density functional theory as our main tool for investigating topological phases in real materials, thereby bridging the gap between experimental advances and progress in theoretical understanding of topological effects in realistic materials.
As a result, we dedicate a large part of our activities to developing first-principles methodologies for addressing the electron and spin properties which are rooted in the topological nature of electrons in solids.
Latest Research Highlight
Engineering Chiral and Topological Orbital Magnetism of Domain Walls and Skyrmions
F. Lux, F. Freimuth, S. Blügel, Y. Mokrousov
Electrons which are slowly moving through chiral magnetic textures can effectively be described as if they where influenced by electromagnetic fields emerging from the real-space topology. This adiabatic viewpoint has been very successful in predicting physical properties of chiral magnets. Here, based on a rigorous quantum-mechanical approach, we unravel the emergence of chiral and topological orbital magnetism in one- and two-dimensional spin systems. We uncover that the quantized orbital magnetism in the adiabatic limit can be understood as a Landau-Peierls response to the emergent magnetic field. Our central result is that the spin-orbit interaction in interfacial skyrmions and domain walls can be used to tune the orbital magnetism over orders of magnitude by merging the real-space topology with the topology in reciprocal space. Our findings point out the route to experimental engineering of orbital properties of chiral spin systems, thereby paving the way to the field of chiral orbitronics.