About the Authors

Jun Li

Affiliation National Laboratory of Solid State Microstructures, School of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, China

Jian Zhang

jzhang@nju.edu.cn (JZ); wangwei@nju.edu.cn (WW)

Affiliation National Laboratory of Solid State Microstructures, School of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, China

Jun Wang

Affiliation National Laboratory of Solid State Microstructures, School of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, China

Wenfei Li

Affiliation National Laboratory of Solid State Microstructures, School of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, China

Wei Wang

jzhang@nju.edu.cn (JZ); wangwei@nju.edu.cn (WW)

Affiliation National Laboratory of Solid State Microstructures, School of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, China

Competing Interests

The authors have declared that no competing interests exist.

Author Contributions

Conceived and designed the experiments: JZ JL WW. Performed the experiments: JL. Analyzed the data: JZ JL WW WL JW. Wrote the paper: JZ JL.