[1] Pukyong Natl Univ, Dept Phys, Busan 48513, South Korea
[2] Yanshan Univ, Sch Sci, State Key Lab Mat Sci & Technol, Qinhuangdao 066004, Hebei, Peoples R China
[3] Yanshan Univ, Sch Sci, Key Lab Microstruct Mat Phys Hebei Prov, Qinhuangdao 066004, Hebei, Peoples R China
[4] Jilin Univ, Coll Phys, Key Lab Phys & Technol Adv Batteries, Coherent Light & Atom & Mol Spect Lab, Changchun 130012, Jilin, Peoples R China