1. Zernike Institute for Advanced Materials, University of Groningen, 9747 AG Groningen, The Netherlands
2. Institute of Molecules and Materials, Radboud University, 6525 ED Nijmegen, The Netherlands
3. Institute for Advanced Simulation, Jülich Supercomputing Centre, Forschungszentrum Jülich, 52425 Jülich, Germany
4. Department of Physics, RWTH Aachen University, 52056 Aachen, Germany