1. State Key Laboratory of Low Dimensional Quantum Physics and Department of Physics Tsinghua University Beijing 100084 China
2. Frontier Science Center for Quantum Information Beijing 100084 China
3. Institute of Materials Research Tsinghua Shenzhen International Graduate School Tsinghua University Shenzhen 518055 China
4. Beijing National Laboratory for Condensed Matter Physics Institute of Physics Chinese Academy of Sciences Beijing 100190 China
5. Songshan Lake Materials Laboratory Dongguan Guangdong 523808 China