Correction to: Nature Communications https://doi.org/10.1038/s41467-018-03302-z, published online 21 March 2018

The original version of this Article contained an error in Eq. 1. A factor of ‘c’ was included in the right-hand term. This has been corrected in the PDF and HTML versions of the Article.

$$p = N_A^ - = c\frac{{N_A}}{{1 + {\mathrm{exp}}\left( {\frac{{E_A - E_F}}{{k_BT}}} \right)}}$$

The correct form of Eq. 1 is:

$$p = N_A^ - = \frac{{N_A}}{{1 + {\mathrm{exp}}\left( {\frac{{E_A - E_F}}{{k_BT}}} \right)}}$$

This has been corrected in the PDF and HTML versions of the Article.