1. Department of Materials Engineering Science, Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama, Toyonaka, Osaka 560-8531, Japan
2. Research Institute for Electronic Science, Hokkaido University, Sapporo, Hokkaido 001-0021, Japan
3. Center for Emergent Functional Matter Science, National Yang Ming Chiao Tung University, Hsinchu 30010, Taiwan
4. Center for Quantum Information and Quantum Biology, Osaka University, Toyonaka, Osaka 560-8531, Japan