1. Institute for Solid State Physics, University of Tokyo, Kashiwa, Chiba 277-8581, Japan
2. CREST, Japan Science and Technology Agency (JST), Kawaguchi, Saitama 332-0012, Japan
3. Department of Physics and Astronomy, Johns Hopkins University, Baltimore, Maryland 21218, USA
4. Center for Emergent Matter Science, RIKEN, Wako, Saitama 351-0198, Japan
5. Institute for Quantum Matter and Department of Physics and Astronomy, Johns Hopkins University, Baltimore, Maryland 21218, USA