[Ren, Yi; Zhou, Guanghui; Liu, Pu] Hunan Normal Univ, Dept Phys, Changsha 410081, Hunan, Peoples R China.
[Ren, Yi; Zhou, Guanghui; Liu, Pu] Hunan Normal Univ, Key Lab Low Dimens Quantum Struct & Manipulat, Minist Educ, Changsha 410081, Hunan, Peoples R China.
[Ren, Yi; Zhou, Guanghui; Liu, Pu] Hunan Normal Univ, Synerget Innovat Ctr Quantum Effects & Applicat H, Changsha 410081, Hunan, Peoples R China.
[Cheng, Fang] Changsha Univ Sci & Technol, Coll Phys & Elect Sci, Changsha 410004, Hunan, Peoples R China.