1. Condensed
Matter Science and Technology Institute, Harbin Institute of Technology, Harbin 150080, China
2. School
of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001, China
3. School
of Electrical Engineering and Automation, Harbin Institute of Technology, Harbin 150001, China
4. Department
of Mathematics and Materials Research Institute, The Pennsylvania State University, University Park, State College, Pennsylvania 16802, United States