[1] Nanjing Univ, Sch Phys, Nanjing 210093, Jiangsu, Peoples R China
[2] Nanjing Univ, Inst Nonperturbat Phys, Nanjing 210093, Jiangsu, Peoples R China
[3] Helmholtz Zentrum Dresden Rossendorf, Bautzner Landstr 400, D-01328 Dresden, Germany
[4] Tech Univ Dresden, D-01062 Dresden, Germany