1. Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
2. College of Construction Engineering, Jilin University, Changchun, Jilin 130061, China
3. HiPSEC and Department of Physics, University of Nevada, Las Vegas, Nevada 89154, USA
4. Neutron Scattering Laboratory, China Institute of Atomic Energy, Beijing 102413, China
5. School of Materials Science and Engineering, Beihang University, Beijing 100191, China
6. LANSCE Division, Los Alamos National Lab, Los Alamos, New Mexico 87545, USA