1. Key Laboratory for Thin Film and Microfabrication Technology of Ministry of Education, University of Michigan—Shanghai Jiao Tong University Joint Institute, Shanghai Jiao Tong University, 200240 Shanghai, China
2. National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, 100190 Beijing, China
3. CAS Center for Excellence in Topological Quantum Computation and School of Physics, University of Chinese Academy of Sciences, 100049 Beijing, China