1. Department of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan
2. Graduate Institute of Applied Physics and Department of Physics, National Taiwan University, Taipei 10617, Taiwan
3. Department of Physics, National Cheng Kung University, Tainan 701, Taiwan
4. Materials Analysis Division, Taiwan Semiconductor Research Institute, National Applied Research Laboratories, Hsinchu 300091, Taiwan
5. Institute of Physics, Academia Sinica, Taipei 11529, Taiwan
6. Physics Division, National Center for Theoretical Sciences, National Taiwan University, Taipei 10617, Taiwan
7. Center for Quantum Frontiers of Research and Technology (QFort), Tainan 701, Taiwan