1. State Key Laboratory of High Performance Ceramics and Superfine MicrostructureShanghai Institute of CeramicsChinese Academy of Science Shanghai 200050 P. R. China
2. State Key Laboratory of Rare Earth Materials Chemistry and ApplicationsCollege of Chemistry and Molecular EngineeringPeking University Beijing 100871 P. R. China
3. University of Chinese Academy of Sciences Beijing 100049 P. R. China
4. National Laboratory of Solid State Microstructures and School of PhysicsNanjing University Nanjing 210093 P. R. China
5. Collaborative Innovation Center of Advanced Microstructures Nanjing 210093 P. R. China
6. National Institute for Materials Science Tsukuba Ibaraki 305‐0003 Japan
7. State Key Laboratory of Low‐Dimensional Quantum PhysicsDepartment of PhysicsTsinghua University Beijing 100084 P. R. China
8. Collaborative Innovation Center of Quantum Matter Beijing 100084 P. R. China
9. School of Physical Science and TechnologyShanghaiTech University Shanghai 201210 P. R. China
10. State Key Laboratory of Functional Materials for InformaticsShanghai Institute of Microsystem and Information TechnologyChinese Academy of Sciences Shanghai 200050 P. R. China