1 State Key Laboratory of Information Photonics and Optical Communications, School of Science, Beijing University of Posts and Telecommunications, Beijing 100876, China
2 Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
3 Beijing Computational Science Research Center, Beijing 100193, China
4 School of Physics and Nuclear Energy Engineering, Beihang University, Beijing 100083, China
5 e-mail: mlei@bupt.edu.cn
6 e-mail: limin.liu@csrc.ac.cn