1. Department of Electrical and Computer Engineering, University of California, Los Angeles, California 90095, United States
2. Inston, Inc., Los Angeles, California 90095, United States
3. Department of Electrical Engineering, Stanford University, Stanford, California 94305, United States
4. National Institute for Materials Science (NIMS), 1-2-1 Sengen, Tsukuba 305-0047, Japan
5. Department of Physics, University of Arizona, Tucson, Arizona 85721, United States
6. Department of Physics and Astronomy, California State University Northridge, Northridge, California 91330, United States