School of Physics;
Nankai University;
Tianjin 300071;
People's Republic of China;
University of California;
Irvine;
CA 92697;
United States of America;
School of Physics and Optoelectronic Technology;
Dalian University of Technology;
Dalian 116024;
People's Republic of China;
Southwestern Institute of Physics;
Chengdu 610041;
People's Republic of China;