An alternative approach is to screen materials using a surrogate model, which nonetheless requires a training dataset of oxygen vacancy migration activation energies computed with NEB. For an N atom host supercell structure, C h (where h denotes "host"), with total energy E h , we define an oxygen vacancy migration path by a tuple of site indices corresponding to the start and end sites, p = (s, e). A vacancy is created at the start or end site and the atomic positions are relaxed at constant volume, yielding structures C s and C e with total energies E s and E e . These two structures and energies, which are themselves independent of the path by which they are connected, provide the fixed endpoints for an n-image NEB calculation, which yields a sequence of energies,