1. Department of Applied Physics and Quantum-Phase Electronics Center (QPEC), The University of Tokyo, Tokyo 113-8656, Japan
2. PRESTO, Japan Science and Technology Agency (JST), Tokyo 102-0076, Japan
3. Department of Physics, Tokyo Institute of Technology, Tokyo 152-8550, Japan
4. RIKEN Center for Emergent Matter Science (CEMS), Wako 351-0198, Japan
5. The Institute for Solid State Physics (ISSP), The University of Tokyo, Kashiwa, Chiba 277-8581, Japan