[1] Peking Univ, State Key Lab Artificial Microstruct & Mesoscop P, Beijing 100871, Peoples R China
[2] Chinese Acad Sci, Inst Phys, Beijing 100190, Peoples R China
[3] Peking Univ, Frontiers Sci Ctr Nanooptoelect, Beijing 100871, Peoples R China
[4] Peking Univ, Collaborat Innovat Ctr Quantum Matter, Beijing 100871, Peoples R China
[5] South Univ Sci & Technol China, Dept Phys, Shenzhen 518055, Peoples R China