1. Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
2. Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
3. Department of Physics and Astronomy, Wayne State University, Detroit, Michigan 48201, USA
4. Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
5. National Center for Supercomputing Applications, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
6. Department of Physics, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA