1. Department of Physics and Astronomy, James Madison University, Harrisonburg, Virginia 22802, USA
2. Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
3. Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
4. Institute for Materials Science, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
5. NORDITA, Roslagstullsbacken 23, 106 91 Stockholm, Sweden
6. Department of Physics, University of North Florida, Jacksonville, Florida 32224, USA