1. Shanghai Institute of Ceramics Chinese Academy of Sciences 585 He‐Shuo Road Shanghai 201899 P. R. China
2. University of Shanghai for Science and Technology 516 Jun‐gong Road Shanghai 200093 P. R. China
3. Institute of Physics of the Czech Academy of Sciences Cukrovarnicka 10/112 Prague 16200 Czech Republic
4. Wuhan National Laboratory for Optoelectronics and School of Optical and Electronic Information Huazhong University of Science and Technology Wuhan Hubei Province 430074 P. R. China
5. Institute of Condensed Matter and Nanosciences Catholic University of Louvain Chemin des étoiles 8, bte L07.03.01 Louvain‐La‐Neuve B‐1348 Belgium