1. School of Physics Sun Yat‐sen University Guangzhou 510275 China
2. School of Materials Sun Yat‐sen University Shenzhen 518107 China
3. State Key Laboratory of Optoelectronic Materials and Technologies Sun Yat‐sen University Guangzhou 510275 China
4. Department of Physics College of Science, Shantou University Shantou 515063 China