1. Department of Electronic and Computer Engineering, The Hong Kong University of Science and Technology, Hong Kong, China
2. Guangdong-Hong Kong-Macao Joint Laboratory for Intelligent Micro-Nano Optoelectronic Technology, The Hong Kong University of Science and Technology, Hong Kong, China
3. Department of Physics and Astronomy, University of California, Riverside, California 92521, USA
4. Department of Physics and Astronomy, King Saud University, Riyadh 11451, Saudi Arabia
5. Department of Physics, Center for Quantum Materials, William Mong Institute of Nano Science and Technology, The Hong Kong University of Science and Technology, Hong Kong, China