1. National Center for Electron Microscopy in Beijing, Key Laboratory of Advanced Materials (MOE), State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing 100084, China
2. National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, New York 11973, United States
3. Department of Physics and Astronomy, University of California, Irvine, California 92697, United States
4. Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, New York 11973, United States