1. Beijing Advanced Innovation Center for Materials Genome EngineeringSchool of Materials Science and EngineeringUniversity of Science and Technology Beijing Beijing 100083 China
2. Department of PhysicsSouthern University of Science and Technology Shenzhen 518055 China
3. State Key Laboratory of Superlattices and MicrostructuresInstitute of Semiconductors Chinese Academy of Sciences Beijing 100083 China
4. Johannes Gutenberg UniversityInstitute of Physics Mainz 55128 Germany