[1] Nanjing Univ, Natl Lab Solid State Microstruct, Nanjing 210093, Peoples R China
[2] Nanjing Univ, Sch Phys, Nanjing 210093, Peoples R China
[3] Nanjing Univ, Collaborat Innovat Ctr Adv Microstruct, Nanjing 210093, Peoples R China
[4] Southern Univ Sci & Technol, Shenzhen Inst Quantum Sci & Engn, Shenzhen 518055, Peoples R China
[5] Southern Univ Sci & Technol, Dept Phys, Shenzhen 518055, Peoples R China