1. International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China.
2. Collaborative Innovation Center of Quantum Matter, Beijing 100871, China.
3. Max Planck Institute for the Structure and Dynamics of Matter, 22761 Hamburg, Germany.
4. CAS Center for Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing 100190, China.
5. Beijing Academy of Quantum Information Sciences, Beijing 100193, China.
6. IBM Research–Almaden, San Jose CA 95120, USA.