DepartmentofPhysics;
TheHongKongUniveristyofScienceandTechnology;
ClearWaterBay;
kowloon;
HongKong;
StateKeyLaboratoryofsiliconMaterials;
ZhejiangUniversity;
Hangzhou310027;
DepartmentofPhysics;
KansasStateUniversity;
Manhattan;
Kansas66506-2601;
USA;