About the Authors

Jun-Jie Chen

Affiliation Department of Physics, Zhejiang University, Hangzhou, Zhejiang, China

Bo Zheng

zheng@zimp.zju.edu.cn

Affiliation Department of Physics, Zhejiang University, Hangzhou, Zhejiang, China

Lei Tan

Affiliation Department of Physics, Zhejiang University, Hangzhou, Zhejiang, China

Competing Interests

The authors have declared that no competing interests exist.

Author Contributions

Conceived and designed the experiments: JJC BZ LT. Performed the experiments: JJC. Analyzed the data: JJC BZ LT. Contributed reagents/materials/analysis tools: JJC BZ. Wrote the paper: JJC BZ LT.