Fig. 2: Analysis of the Born effective charge (BEC) tensors in different phases of high-pressure water.
From: Machine learning interatomic potential can infer electrical response
a corresponds to partially ionic liquid water, b shows face-centred cubic (FCC) superionic phase (ice XVIII), and c is ice X. The oxygen-hydrogen bonds are drawn with a cutoff of 1.1 Å. d compares the BEC tensors (Z*) computed from DFT and predicted using the LES method, for 100 configurations of each phase at the specified condition. The CACE-LR was trained based on the energies and forces from the superionic water dataset49. The main panels compare the diagonal elements of BEC (\({Z}_{\alpha \alpha }^{* }\)), and the insets show the off-diagonal elements (\({Z}_{\alpha \beta }^{* }\) with α ≠β). e illustrates the correlation between the mean diagonal values of Z* of all hydrogen atoms, and the distances to their nearest two oxygen atoms.
