Correction to: Nature https://doi.org/10.1038/s41586-019-1630-4Published online 07 October 2019

In the Acknowledgements section of this Article, the statement ‘B.A.B. was supported by the US Department of Energy through grant number DE-SC0016239, the US National Science Foundation EAGER through grant number NOA-AWD1004957, Simons Investigator grants ONR-N00014-14-1-0330 and NSF-MRSEC DMR- 1420541, the Packard Foundation and the Schmidt Fund for Innovative Research.’ should be replaced by ‘First-principles calculations were funded by the US Department of Energy through grant number DE-SC0016239. B.A.B. acknowledges additional support from the US National Science Foundation EAGER through grant number NOA-AWD1004957, Simons Investigator grants ONR-N00014-14-1-0330 and NSF-MRSEC DMR-1420541, the Packard Foundation and the Schmidt Fund for Innovative Research.’. The original Article has been corrected online.