[1] Harbin Inst Technol, Dept Phys, Harbin 150001, Peoples R China
[2] Zhanjiang Normal Coll, Dept Phys, Zhanjiang 524048, Peoples R China
[3] Harbin Engn Univ, Sch Sci, Harbin 150001, Peoples R China
[4] Suzhou Univ, Sch Phys Sci & Technol, Suzhou 215006, Peoples R China