1. a Blagoveschensk State Pedagogical University , Blagoveschensk , 675002 , Russia
2. b Department of Physics , National Cheng Kung University , Tainan , 70101 , Taiwan , ROC
3. c Center for Micro/Nano Science of Technology , National Cheng Kung University , Tainan , 70101 , Taiwan , ROC
4. d Faculty of Physics, St. Petersburg State University , St. Petersburg , Petrodvorets , 198504 , Russia
5. e Faculty of Physics and Geosciences, University of Leipzig , Leipzig , D-04103 , Germany