1. Department of Physics, Nagoya University, Nagoya 464-8602, Japan
2. Université de Lyon, Laboratoire de Chimie, Ecole Normale Supérieure de Lyon, CNRS, F-69364 Lyon, France
3. Laboratoire de Chimie Quantique, UMR 7177 CNRS/Université de Strasbourg, F-67000 Strasbourg, France
4. Nanosystem Research Institute (NRI) “RICS”, AIST, Tsukuba, Ibaraki 305-8568, Japan
5. Condensed Matter Theory Laboratory, RIKEN, Wako, Saitama 351-0198, Japan
6. JST, CREST, Wako, Saitama 351-0198, Japan