[1] Fudan Univ, State Key Lab Surface Phys, Shanghai 200433, Peoples R China
[2] Fudan Univ, Dept Phys, Shanghai 200433, Peoples R China
[3] Shanghai Res Ctr Quantum Sci, Shanghai 201315, Peoples R China
[4] Fudan Univ, Inst Nanoelect Devices & Quantum Comp, Shanghai 200433, Peoples R China
[5] Hefei Natl Lab, Hefei 230088, Peoples R China