1. State
Key Laboratory
of Low-Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing 100084, China
2. International
Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China
3. Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
4. Collaborative Innovation Center of Quantum Matter, Beijing 100871, China
5. Frontier Science Center for Quantum Information, Beijing 100084, China
6. Key Laboratory for the
Physics and Chemistry of Nanodevices, Department of Electronics, Peking University, Beijing 100871, China