**Author details**

Yuhua Wang1,2\*, Xinlong Ma1,2, Hao Li1,2, Bin Liu1,2, Huihui Li1,2, Shu Yin3 and Tsugio Sato3

\*Address all correspondence to: wyh@lzu.edu.cn

1 Key Laboratory for Special Function Materials and Structure Design of the Ministry of Education, Lanzhou University, Lanzhou, P. R. China

2 Department of Materials Science, School of Physical Science and Technology, Lanzhou University, Lanzhou, P. R. China

3 Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Aobaku, Sendai, Japan
