1. Department of Electrophysics National Yang Ming Chiao Tung University Hsinchu 300 Taiwan
2. Center for Quantum Technology and Department of Physics National Tsing Hua University Hsinchu 300 Taiwan
3. Research Center for Applied Sciences Academia Sinica Taipei 115 Taiwan
4. Center for Emergent Functional Matter Science National Yang Ming Chiao Tung University Hsinchu 300 Taiwan
5. Institute for Solid State Physics The University of Tokyo Kashiwa 277‐8568 Japan
6. Physics Division National Center for Theoretical Sciences Taipei 106 Taiwan
7. Institute of Physics Academia Sinica Taipei 115 Taiwan
8. National Synchrotron Radiation Research Center Hsinchu 300 Taiwan