1. Department of Physics, The University of Hong Kong, Pokfulam Road, Hong Kong
2. Shenzhen Institute for Quantum Science and Engineering, and Department of Physics, Southern University of Science and Technology, Shenzhen 518055, China
3. Department of Mechanical Engineering, The University of Hong Kong, Pokfulam Road, Hong Kong
4. Core Characterization Facility, Southern University of Science and Technology, No. 1088, Xueyuan Rd., Shenzhen, 518055, Guangdong, P. R. China