1. Applied Theoretical Physics-Computational Physics, Physikalisches Institut, Albert-Ludwigs-Universität Freiburg, D-79104 Freiburg, Germany
2. Korea Institute for Advanced Study, Seoul 02455, Republic of Korea
3. Jožef Stefan Institute, SI-1000 Ljubljana, Slovenia
4. Research Group for Simulations of Energy Materials, Helmholtz-Zentrum Berlin für Materialien und Energie, D-14109 Berlin, Germany