1. Institute of Physics, Academia Sinica, Taipei 11529, Taiwan
2. Department of Engineering and System Science, National Tsing Hua University, Hsinchu 30013, Taiwan
3. Taiwan International Graduate Program, Taipei 11529, Taiwan
4. Department of Physics, National Chung Hsing University, Taichung City 40227, Taiwan
5. Graduate School of Materials Science, National Yunlin University of Science and Technology, Yunlin 64002, Taiwan
6. Bachelor Program in Semiconductor Materials and Fabrication, Ming Chi University of Technology, New Taipei City 243303, Taiwan
7. Department of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan
8. Center for Theory and Computation, National Tsing Hua University, Hsinchu 30013, Taiwan
9. Physics Division, National Center for Theoretical Sciences, Taipei 10617, Taiwan
10. Department of Physics, National Central University, Jhongli 32001, Taiwan
11. National Synchrotron Radiation Research Center, Hsinchu Science Park, Hsinchu 30076, Taiwan
12. Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 10617, Taiwan
13. Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, USA
14. Graduate Institute of Applied Physics, National Chengchi University, Taipei 11605, Taiwan