1. A. J. Drexel Nanomaterials Institute and Department of Materials Science and Engineering, Drexel University, Philadelphia, Pennsylvania 19104, United States
2. School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan, Hubei 430074, People’s Republic of China
3. Department of Applied Physics and Applied Mathematics, Columbia University, New York, New York 10027, United States
4. Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830, United States
5. Institute of Chemical Sciences and Technologies “G.Natta” Consiglio Nazionale delle Ricerche (SCI-TEC), via A. Corti 12, 20133 Milano, Italy
6. Istituto di Cristallografia-Sincrotrone Elettra, Strada Statale 14-Km 163, 5 Area Science Park, Basovizza, Trieste 34149, Italy