1. Institute of Engineering Innovation, School of Engineering, The University of Tokyo, 2-11-16 Yayoi, Bunkyo-ku, Tokyo 113-8656, Japan
2. School of Physics and Astronomy, Monash University, Clayton, Victoria 3800, Australia
3. Electron Optics
Division JEOL Limited, Tokyo 196-8558, Japan
4. Advanced Technology
Research Division, SONY Corporation, 4-14-1, Asahi, Atsugi-shi, Kanagawa 243-0014, Japan
5. Nanostructures Research
Laboratory, Japan Fine Ceramic Center, 2-4-1 Mutsuno, Atsuta-ku, Nagoya 456-8587, Japan