1. Department of Applied Physics, The Hong Kong Polytechnic University, Kowloon 999077, Hong Kong
2. Department of Physics, Southern University of Science and Technology, Shenzhen 518055, China
3. State Key Laboratory of Material Processing and Die & Mould Technology, Huazhong University of Science and Technology, Wuhan 430074, P. R. China
4. School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore 639798, Singapore
5. Center for Quantum Materials & Devices and College of Physics, Chongqing University, Chongqing 401331, P. R. China