1. State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200433, China
2. Institute for Nanoelectronic Devices and Quantum Computing, Fudan University, Shanghai 200433, China
3. Laboratory for Computational Physical Sciences (MOE), Fudan University, Shanghai 200433, China
4. Department of Electronic Engineering, Royal Holloway University of London, Egham TW20 0EX, UK
5. School of Electronic Science and Engineering, Nanjing University, Nanjing 210093, China
6. Materials Engineering, The University of Queensland, Brisbane QLD 4072, Australia
7. Department of Physics, National University of Singapore, Singapore 117542, Singapore
8. Centre for Advanced 2D Materials and Graphene Research Centre, National University of Singapore, Singapore 117546, Singapore
9. Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
10. School of Information Science and Technology, ShanghaiTech University, Shanghai 201210, China
11. Centre for Microscopy and Microanalysis, The University of Queensland, Brisbane QLD 4072, Australia
12. Collaborative Innovation Center of Advanced Microstructures, Nanjing 210093, China