1. Center for Emergent Matter Science (CEMS) RIKEN 2‐1 Hirosawa Wako Saitama 351‐0198 Japan
2. Wuhan National Laboratory for Optoelectronics Huazhong University of Science and Technology Wuhan 430074 China
3. Thin‐Film Device Laboratory, RIKEN 2‐1 Hirosawa Wako Saitama 351‐0198 Japan
4. Department of Electrical Engineering and Information Systems The University of Tokyo 7‐3‐1 Hongo, Bunkyo‐ku Tokyo 113‐8656 Japan