1. Surface and Interface Science Laboratory RIKEN 2-1 Hirosawa, Wako Saitama 351-0198 Japan
2. National Institute of Physics University of the Philippines, Diliman Quezon City 1101 Philippines
3. Research Center for Development of Far-Infrared Region University of Fukui 3-9-1 Bunkyo Fukui 910-8507 Japan
4. Division of Materials and Manufacturing Science, Graduate School of Engineering Osaka University 2-1 Yamadaoka, Suita Osaka 565-0871 Japan
5. Materials Science and Engineering Program University of the Philippines, Diliman Quezon City 1101 Philippines