1. Advanced ICT Research Institute, National Institute of Information and Communications Technology, 588-2
Iwaoka, Nishi-ku, Kobe 651-2492, Japan
2. Division of Frontier Materials
Science, Graduate School of Engineering Science, and Center for Quantum
Materials Science under Extreme Conditions, Osaka University, 1-3 Macikaneyama-cho, Toyonaka, Osaka 560-8531, Japan