1. Department of Physics, Saga University, Saga 840-8502, Japan
2. National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan
3. Institute for Solid State Physics, University of Tokyo, Kashiwa, Chiba 277-8581, Japan
4. Institute for the Advancement of Higher Education, Okayama University of Science, Okayama 700-0005, Japan
5. Department of Applied Quantum Physics, Kyushu University, Fukuoka 819-0395, Japan
6. Department of Applied Chemistry and Biochemistry, Kumamoto University, Kumamoto 860-8555, Japan
7. Materials Research and Development Laboratory, Japan Fine Ceramic Center (JFCC), Nagoya 456-8587, Japan
8. Advanced Device Laboratory, The Institute of Physical and Chemical Research (RIKEN), Wako, Saitama 351-0198, Japan
9. CEMS, RIKEN, Wako, Saitama 351-0198, Japan