Scientific Reports 6: Article number: 20506; published online: 16 February 2016; updated: 20 May 2016.

This Article contains typographical errors.

Equation 3,

should read:

In the legend of Table 2,

“Derived parameters of the function ρ (τ). Note: .”

should read:

“Derived parameters of the function ρ (τ). Note: .”

In the Methods section,

τ for the imaginary susceptibility part”

should read:

τ for the imaginary susceptibility part”

In the Acknowledgements section,

“Jiangsu Provincial Natural Science Foundation of China (No. 1063-515024111)”

should read:

“Jiangsu Provincial Natural Science Foundation of China (No. BK20150823)”