Affiliation: | State Key Laboratory of Solid State Microstructures, Nanjing University, Nanjing 210093, China; Department of Physics, Nanjing Normal University, Nanjing 210097, China; Department of Physics, Nanjing Normal University, Nanjing 210097,China; State Key Laboratory of Solid State Microstructures, Nanjing University, Nanjing 210093, China |