Institution: | aDepartment of Physics, Graduate School of Science, Tohoku University, Sendai, Miyagi 980-8578, Japan;bDepartment of Physics, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan;cResearch Center for Low Temperature and Materials Sciences, Kyoto University, Kyoto 606-8502, Japan;dNTT Basic Research Laboratories, NTT Corporation, 3-1 Morinosato-Wakamiya, Atsugi, Kanagawa 243-0198, Japan |