Correction to: Nature Nanotechnology https://doi.org/10.1038/s41565-020-00777-0, published online 26 October 2020.

In the version of this Article originally published online, the units in the y-axis labels in Fig. 2g and the inset of Fig. 2g were incorrect; ‘pA’ should have been ‘μA’ (main figure) and ‘μA’ should have been ‘pA’ (inset figure). This has now been corrected in all versions of the Article.