1. State
Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi’an 710072, People’s Republic of China
2. National
Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230029, People’s Republic of China
3. Key
Laboratory of Artificial Structures and Quantum Control (Ministry
of Education), Department of Physics, Shanghai Jiao Tong University, Shanghai 200240, People’s Republic of China