1. Key Laboratory for Renewable Energy Chinese Academy of Sciences Beijing Key Laboratory for New Energy Materials and Devices Institute of Physics Chinese Academy of Sciences Beijing 100190 China
2. School of Physical Sciences University of Chinese Academy of Sciences Beijing 100190 China
3. Laboratory for Advanced Materials and Electron Microscopy Institute of Physics Chinese Academy of Sciences Beijing 100190 China
4. Department of Mechanical and Materials Engineering University of Western Ontario London Ontario N6A 5B9 Canada
5. Department of Physics and Astronomy California State University Northridge Northridge CA 91330–8268 USA
6. Synchrotron Soleil L'Orme des Merisiers St‐Aubin 91192 Gif‐sur‐Yvette France
7. State Key Laboratory for Surface Physics Institute of Physics Chinese Academy of Sciences Beijing 100190 China