1. Joint Research Center for Atom Technology (JRCAT), Tsukuba 305-0046
2. Research Center for Advanced Science and Technology, University of Tokyo, Tokyo 153-8904
3. Correlated Electron Research Center (CERC), National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba 305-8562
4. Institute for Materials Research, Tohoku University, Sendai 980-8577
5. Department of Applied Physics, University of Tokyo, Tokyo 113-8656