1. Department
of Materials Science and Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
2. Department
of Materials, University of Oxford, Parks Road, Oxford, OX1 3PH, United Kingdom
3. JEOL Ltd., 3-1-2 Musashino, Akishima, Tokyo 196-8558, Japan
4. Electron Physical Sciences Imaging Center, Diamond Light Source Ltd, Didcot, Oxfordshire, OX11
0DE, United Kingdom