1. Quantum Science and Engineering Center; Kyoto University; Gokasho Uji Kyoto 611-0011 Japan
2. Department of Nuclear Engineering; Kyoto University; Gokasho Uji Kyoto 611-0011 Japan
3. Surface Analysis Laboratories, Toray Research Center, Inc.; 3-7 Sonoyama 3-chome Otsu Shiga 520-8567 Japan
4. CREST, Japan Science and Technology Agency (JST); Chiyoda Tokyo 102-0075 Japan
5. Department of Electronic Science and Engineering; Kyoto University; Nishikyo-ku Kyoto 615-8510 Japan