1. Department of Applied Physics, Yale University, New Haven, CT 06520
2. École Supérieure de Physique et de Chimie Industrielles de la ville de Paris, Paris Sciences et Lettres Research University, CNRS, Institut Langevin, F-75005 Paris, France
3. Ming Hsieh Department of Electrical and Computer Engineering, University of Southern California, Los Angeles, CA 90089
4. Institute of Materials Science and Nanotechnology, National Nanotechnology Research Center, Bilkent University, 06800 Ankara, Turkey
5. Physics Department, Missouri University of Science & Technology, Rolla, MO 65409