1. School of Physics and Electronic Engineering, Guangzhou University, 230 Wai Huan Xi Road, Guangzhou Higher Education Mega Center, Guangzhou 510006, China
2. State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, 585 Heshuo Road, Jiading, Shanghai 201899, China
3. Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore 117542