1. Institute of Applied Physics, Hamburg University, Jungiusstrasse 11, 20355 Hamburg, Germany.
2. I. Institute of Theoretical Physics, Hamburg University, Jungiusstrasse 9, 20355 Hamburg, Germany.
3. Institute of Theoretical Physics, Bremen University, Otto-Hahn-Allee 1, 28359 Bremen, Germany.
4. Bremen Center for Computational Materials Science, Bremen University, Am Fallturm 1a, 28359 Bremen, Germany.
5. Peter Grünberg Institute and Institute for Advanced Simulation, Forschungszentrum Jülich and JARA (Jülich Aachen Research Alliance), 52425 Jülich, Germany.