1. Sorbonne Université, Institut des Nanosciences de Paris, UMR7588 au CNRS, 4 Place Jussieu, 75005 Paris, France
2. Helmholtz Zentrum Dresden Rossendorf, Institute of Ion Beam Physics and Materials Research, Bautzner Landstrasse 400, D-013128 Dresden, Germany
3. Lehrstuhl für Theoretische Physik, Universität Paderborn, 33098 Paderborn, Germany
4. Department of Physics, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, Ohio 44106-7079, USA
5. Bremen Center for Computational Materials Science, University of Bremen, P.O. Box 330440, D-28334 Bremen, Germany