1. Department of Physics, The University of Texas at El Paso, El Paso, Texas 79968, USA
2. Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, USA
3. Institute of Physics, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
4. National Centre for Computational Design and Discovery of Novel Materials (MARVEL), Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
5. Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA