Correction to: Nature https://www.nature.com/articles/s41586-018-0091-5, published online 09 May 2018.

In Fig. 3f of this Letter, owing to an error in the production process, the y-axis values are incorrect, and should go from 4 to −8 (rather than from 4 to −4), and in Fig. 3h, the y-axis values (18, 20, 22, 24) should appear next to the major tick marks (rather than the minor ticks). In addition, in Fig. 1b, the arrows at the top and the bottom of the electron-scale current sheet were going in the wrong direction. These errors have been corrected online.