1. State Key Laboratory for Mechanical Behavior of Materials, Xi’an Jiaotong University, Xi’an 710049, Shaanxi, China
2. College of Physics and Information Technology, Shaanxi Normal University, Xi’an 710062, Shaanxi, China
3. Department of Physics and Opt-electronic Engineering, Xi’an University of Arts and Science, Xi’an 710065, Shaanxi, China
4. Department of Physics and Department of Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong, China