1. Department of Photonics, College of Electrical and Computer Engineering, National Chiao Tung University, Hsinchu 30010, Taiwan
2. Department of Physics, University of Hong Kong, Pokfulam Road, Hong Kong 999077, China
3. National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan
4. Department of Physics, Southern University of Science and Technology, No. 1088, Xueyuan Road, Shenzhen, Guangdong 518055, China
5. Center of Excellence for Advanced Materials and Sensing Devices, Division for Materials Physics, Laboratory for Synthesis and Crystallography of Functional Materials, Ruđer Bošković Institute, Bijenička 54, Zagreb 52210, Croatia