1. The Ultramicroscopy Research Center, Kyushu University, 744 Motooka, Nihsi-ku, Fukuoka 819-0395, Japan
2. Graduate School of Information Science and Technology, Osaka University, 1-5 Yamadaoka, Suita, Osaka 565-0871, Japan
3. Nanostructures Research Laboratory, Japan Fine Ceramics Center, 2-4-1 Mutsuno, Atsuta-ku, Nagoya, Aichi 456-8587, Japan
4. Department of Applied Quantum Physics and Nuclear Engineering, Kyushu University, 744 Motooka, Nihsi-ku, Fukuoka 819-0395, Japan
5. Research and Development Group, Hitachi, Ltd., 2520 Hatoyama, Saitama 350-0395, Japan
6. RIKEN Center for Emergent Matter Science (CEMS), 2-1 Wako, Saitama 351-0198, Japan
7. Department of Applied Physics and Quantum-Phase Electronics Center (QPEC), University of Tokyo, Bunkyo-ku, Tokyo 113-8656, Japan