1. State
Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, People’s Republic of China
2. School
of Physics and Electronic Science, Changsha University of Science and Technology, Changsha 410114, People’s Republic of China
3. Synergetic
Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China