1. Institute for Solid State Physics (ISSP), The University of Tokyo, Kashiwa, Chiba, Japan.
2. Hiroshima Synchrotron Radiation Center (HSRC), Hiroshima University, Higashi-Hiroshima, Hiroshima, Japan.
3. Institute of Physics, Chinese Academy of Sciences, Beijing, China.
4. Department of Physics and Astronomy, National Tsing Hua University, Hsinchu, Taiwan, Republic of China.
5. National Synchrotron Radiation Research Center (NSRRC), Hsinchu, Taiwan, Republic of China.
6. Department of Physics and Astronomy, University of Missouri, Columbia, MO, USA.
7. Department of Physics and Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, IL, USA.