Scientific Reports 5: Article number: 12341; published online: 24 July 2015; updated: 20 October 2015.

In this Article, the Figure labels were omitted from Figure 1. The correct Figure 1 appears below.

figure 1

In addition, there is a typographical error in the Acknowledgements section.

“HT also thanks Prof. S. Qiao of Fudan University, China and Prof. K. F. Kelly of Rice University, USA, for fruitful discussions and Profs. K. Maeda and Y. Horibe of Kyutech, Japan, for support with the experiments.”

should read:

“HT also thanks Prof. S. Qiao of Fudan University, China and Prof. K. F. Kelly of Rice University, USA, for fruitful discussions and Profs. T. Maeda and Y. Horibe of Kyutech, Japan, for support with the experiments.”