1. Department of Physics, Faculty of Science, Niigata University, Niigata 950-2181, Japan
2. Department of Physics, Graduate School of Science, Kobe University, Kobe 657-8501, Japan
3. Center for Quantum Information and Quantum Biology, Osaka University, Toyonaka, Osaka 560-0043, Japan
4. JST, PRESTO, Kawaguchi, Saitama 332-0012, Japan
5. Computational Materials Science Research Team, RIKEN Center for Computational Science (R-CCS), Kobe 650-0047, Japan