Open positions for PhD, Master and Bachelor theses and Postdoctoral positions at the Institute of Physics, Solid State Physics:
Our group works on the area of spintronics and nano-electronics. We work as well on other aspects of solid state theory, with a view towards multi-disciplinary approaches. Our group is very dynamic and we try to create an environment with diverse characters and expertise in order to attain a much more powerful approach to the physical challenges that we try to solve.
Libor Smejkal has predicted a new type of phenomena in the family of spontaneous Hall effects connected to a new type of exchange splitting that depends on the momentum of the electron quasiparticle.
Abstract: Electrons, commonly moving along the applied electric field, acquire in certain magnets a dissipationless transverse velocity. This spontaneous Hall effect, found more than a century ago, has been understood in terms of the time-reversal symmetry breaking by the internal spin structure of a ferromagnetic, noncolinear antiferromagnetic, or skyrmionic form. Here, we identify previously overlooked robust Hall effect mechanism arising from collinear antiferromagnetism combined with nonmagnetic atoms at noncentrosymmetric positions. We predict a large magnitude of this crystal Hall effect in a room temperature collinear antiferromagnet RuO2 and catalog, based on symmetry rules, extensive families of material candidates. We show that the crystal Hall effect is accompanied by the possibility to control its sign by the crystal chirality. We illustrate that accounting for the full magnetization density distribution instead of the simplified spin structure sheds new light on symmetry breaking phenomena in magnets and opens an alternative avenue toward low-dissipation nanoelectronics.
The DFG has funded the CRC TRR288 ELASTO-Q-MAT initiative. It involves the JGU (Sinova co-speaker), Goethe University Frankfurt (Roser Valenti as coordinator and speaker), the Karlsruhe Institute of Technology (Joerg Schmalian co-speaker), and the Max Plank Institutes in Mainz and Dresden. This initiative has the goal to understand, advance, and exploit new physical phenomena emerging from a particularly strong coupling between a material's elasticity and its electronic quantum phases. To this end, we will study the effects of elastic tuning and elastic response of various types of electronic order in representative classes of quantum materials that share a high sensitivity to intrinsic strain or externally applied stress fields