[1] Fuyang Normal Univ, Dept Phys, Fuyang 236000, Peoples R China
[2] Univ Sci & Technol China, Microscale, Hefei 230026, Peoples R China
[3] Univ Sci & Technol China, Dept Modern Phys, Hefei 230026, Peoples R China
[4] Fuyang Vocat Coll Sci & Technol, Fuyang 236037, Anhui, Peoples R China
[5] Hunan Inst Technol, Sch Elect & Informat Engn, Hengyang 421002, Peoples R China