Addendum: Freezing on a sphere

Addendum to: Nature https://doi.org/10.1038/nature25468, published online 14 February 2018.

After the publication of our Letter, we were made aware of some pioneering simulations by Prestipino Giarrita et al. that investigated the icosahedral ordering of defects in assemblies of hard particles packed on the surfaces of spheres^1,2. This work anticipated the notion that lattice defects were an inevitable part of ordered structures assembled on spherical shells, and they defined a pair defect-density correlation², g_def, similar to the g₅₅ function that we plot in Fig. 2a of our Letter. This work^1,2 represents a solid contribution to the field and merits wider recognition.