1. School of Materials Science and Engineering University of Science and Technology Beijing Beijing 100083 P. R. China
2. Guangdong Provincial Key Laboratory of Optical Information Materials and Technology & Institute for Advanced Materials South China Academy of Advanced Optoelectronics South China Normal University Guangzhou 510006 P. R. China
3. National Center for International Research on Green Optoelectronics South China Normal University Guangzhou 510006 P. R. China
4. Tianjin Key Laboratory of Low Dimensional Materials Physics and Preparation Technology School of Science Tianjin University Tianjin 300354 P. R. China
5. State Key Laboratory of Superlattices and Microstructures Institute of Semiconductors Chinese Academy of Sciences Beijing 100083 P. R. China
6. Key Laboratory for Magnetism and Magnetic Materials of Ministry of Education Lanzhou University Lanzhou 730000 P. R. China
7. State Key Laboratory of Heavy Oil Processing China University of Petroleum‐Beijing Beijing 102249 P. R. China
8. Laboratory of Solid State Microstructures Nanjing University Nanjing 211102 P. R. China