[1] AIST, CERC, Tsukuba, Ibaraki 3058562, Japan
[2] Univ Tokyo, Dept Appl Phys, Tokyo 1138656, Japan
[3] Kyoto Univ, Res Ctr Low Temp & Mat Sci, Kyoto 6068502, Japan
[4] ERATO, Japan Sci & Technol Corp, Kawaguchi 3300012, Japan
[5] Kyoto Univ, Grad Sch Sci, Div Chem, Kyoto 6068502, Japan
[6] Hokkaido Univ, Res Inst Elect Sci, Sapporo, Hokkaido 0600812, Japan