1. Key Lab of Artificial Micro- and Nano-structures of Ministry of Education, School of Physics and Technology, Wuhan University, Wuhan 430072, People's Republic of China
2. State Key Laboratory of Silicate Materials for Architecture (Wuhan University of Technology), Wuhan 430070, People's Republic of China
3. Department of Materials Science and Engineering, University of North Texas, Denton, Texas 76203, USA