1. Institute of Industrial Science, University of Tokyo 1 , 4-6-1 Komaba, Meguro, Tokyo 153-8505, Japan
2. Fujitsu Ltd 2 ., 10-1 Morinosato-Wakamiya, Atsugi, Kanagawa 243-0197, Japan
3. Research Center for Electronic and Optical Materials, National Institute for Materials Science 3 , 1-1 Namiki, Tsukuba 305-0044, Japan
4. Research Center for Materials Nanoarchitectonics, National Institute for Materials Science 4 , 1-1 Namiki, Tsukuba 305-0044, Japan