1. CAS Center for Excellence in NanoscienceCAS Key Laboratory of Nanosystem and Hierarchical FabricationNational Center for Nanoscience and Technology Beijing 100190 China
2. Sino‐Danish CollegeUniversity of Chinese Academy of Science Beijing 100049 China
3. Center of Materials Science and Optoelectronics EngineeringUniversity of Chinese Academy of Science Beijing 100049 China
4. School of Physics and TechnologyWuhan University Wuhan 430072 China