1. Faculty of Science and Engineering, Iwate University, Morioka, Iwate 020-8551, Japan
2. Graduate School of Engineering, Osaka University, Suita, Osaka 565-0871, Japan
3. Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan
4. Correlated Electronics Group, Electronics and Photonics Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki 305-8565, Japan