1. Beijing Institute of Nanoenergy and Nanosystems Chinese Academy of Sciences Beijing 100083 P. R. China
2. School of Nanoscience and Technology University of Chinese Academy of Sciences Beijing 100049 P. R. China
3. Beijing Advanced Innovation Center for Materials Genome Engineering Institute for Advanced Materials and Technology University of Science and Technology Beijing Beijing 100083 P. R. China
4. School of Materials Science and Engineering Georgia Institute of Technology Atlanta GA 30332‐0245 USA