Correction to: Nature Nanotechnology, published online 12 October 2020.

In the version of this News & Views article originally published online, ref. 7 “Reed, A. M. et al. Nat. Nanotechnol. (2020).” was incorrect; it should have been “Zhang, K. et al. Nat. Nanotechnol. (2020).” This has now been corrected in all versions of the News & Views article.