1. Department of Electronics, Nankai University, Tianjin 300071, China
2. Beijing Computational Science Research Center, Beijing 10084, China
3. School of Physics, Nankai University, Tianjin 300071, China
4. Key Laboratory of Microstructures
and Institute of Materials Science, Shanghai University, Shanghai 200072, China
5. State Key Laboratory of Metastable
Materials Science and Technology, Yanshan University, Qinhuangdao 066004, China