1. Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
2. Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
3. Rutgers Center for Emergent Materials and Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey 08854, USA
4. Department of Physics and Engineering Physics, Tulane University, New Orleans, Louisiana 70118, USA
5. Department of Physics and Astronomy, Nebraska Center for Materials and Nanoscience, University of Nebraska, Lincoln, Nebraska 68588, USA