Scientific Reports 4, Article number: 7542 (2014); Published: 18 December 2014; Updated: 4 March 2015

In the original version of the Article, the first affiliation ‘Laboratory for Computational Physical Sciences (MOE), State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200433, China’ was omitted for author Hua Wu. This has now been corrected in both the HTML and PDF versions of the Article.