1. Department of Applied Chemistry, Chubu University, 1200 Matsumoto, Kasugai, Aichi 487-8501, Japan
2. Next-Generation Semiconductor Group, National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan
3. Department of Materials Science, Osaka Prefecture University, 1-1 Gakuencho,
Naka-ku, Sakai, Osaka 599-8531, Japan
4. High Pressure Group, National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan