1. Center
for Crystal Science and Technology, University of Yamanashi, 7-32 Miyamae, Kofu 400-8511, Japan
2. National Institute
for Materials Science, 1-2-1 Sengen, Tsukuba 305-0047, Japan
3. Department
of Electrical and Electronic Engineering, Tokyo Metropolitan University, 1-1 Minami-osawa, Hachioji, Tokyo 192-0397, Japan