School;
of;
Physics;
and;
Microelectronics;
Science,;
Hunan;
University,;
Changsha;
410082,;
China;
School;
of;
Mathematics;
and;
Physics,;
University;
of;
South;
China,;
Hengyang;
421001,;
China;
College;
of;
Physics;
and;
Information;
Science,;
Hunan;
Normal;
University,;
Changsha;
410081,;
China;