1. Department of Electrical Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
2. Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
3. Department of Nuclear and Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
4. Department of Materials Science and Engineering, Texas A&M University, College Station, Texas 77843, United States
5. Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
6. Department of Physics and Astronomy, Center for Materials Theory, Rutgers University, Piscataway, New Jersey 08854, United States
7. Department of Physics, Harvard University, Cambridge, Massachusetts 02138, United States
8. John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, United States