1. Department of Physics, National Central University, Taoyuan 32001, Taiwan
2. Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 10617, Taiwan
3. Molecular Science and Technology Program, Taiwan International Graduate Program, Academia Sinica, Taipei 10617, Taiwan
4. Department of Physics, National Taiwan University, Taipei 10617, Taiwan
5. Nanoscience and Technology Program, Taiwan International Graduate Program, Academia Sinica, Taipei 115, Taiwan
6. International Graduate Program of Molecular Science and Technology, National Taiwan University, Taipei, 10617, Taiwan
7. Center for Condensed Matter Sciences, National Taiwan University, Taipei 10617, Taiwan
8. Center of Atomic Initiative for New Materials, National Taiwan University, Taipei 10617, Taiwan