1. Department of Physics and Center
of Materials Physics and Chemistry, Beihang University, Beijing 100191, P. R. China
2. Institute for Superconducting
and Electronic Materials (ISEM), University of Wollongong, Wollongong, NSW 2522, Australia
3. School of Materials Science and
Engineering, Beihang University, Beijing
100191, P. R. China
4. State
Key Laboratory of Inorganic
Synthesis and Preparative Chemistry, College of Chemistry, Jilin University, Changchun 130012, P. R. China
5. Beijing Synchrotron Radiation
Facility, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, P. R. China