1. Collaborative Innovation Center of Quantum Matter, Beijing, P. R. China
2. EMAT
(Electron Microscopy for Materials Science), University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium
3. Department
of Physics, Tsinghua University, Beijing 100084, P. R. China
4. School of
Physics, Beijing Institute of Technology, Beijing, 100081, P. R. China
5. King Saud University, Riyadh, 11451, Saudi Arabia