[1] Chinese Acad Sci, Joint Lab Adv Technol Measurments, Beijing 100080, Peoples R China
[2] Chinese Acad Sci, Inst Phys, State Key Lab Surface Phys, Beijing Natl Lab Condensed Matter Phys, Beijing 100080, Peoples R China
[3] Sichuan Normal Univ, Dept Phys, Chengdu 610066, Peoples R China
[4] Inst Max Von Laue Paul Langevin, F-38042 Grenoble, France
[5] LD Landau Theoret Phys Inst, Moscow 117940, Russia