1. Beijing Advanced Innovation Center for Materials Genome Engineering University of Science and Technology Beijing Beijing 100083 P. R. China
2. State Key Laboratory of New Ceramics and Fine Processing Tsinghua University Beijing 100084 P. R. China
3. Department of Condensed Matter Physics and Materials Science Brookhaven National Laboratory Upton NY 11973 USA
4. Key Laboratory of Computational Physical Sciences (Ministry of Education) Institute of Computational Physical Sciences State Key Laboratory of Surface Physics and Department of Physics Fudan University Shanghai 200433 P. R. China
5. Shanghai Qi Zhi Institute Shanghai 200232 P. R. China
6. Key Laboratory of Material Physics School of Physics and Microelectronics Zhengzhou University Zhengzhou 450052 P. R. China
7. Institute for Nanoelectronic Devices and Quantum Computing Fudan University Shanghai 200433 P. R. China