1. Department of Physics, Kyoto University, Kyoto 606-8502, Japan
2. Yukawa Institute for Theoretical Physics, Kyoto University, Kyoto 606-8502, Japan
3. Wuhan National High Magnetic Field Center and School of Physics, Huazhong University of Science and Technology, 430074 Wuhan, China
4. Institute for Solid State Physics, The University of Tokyo, Kashiwa, Chiba 277-8581, Japan