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. 2017 Feb 17;8:14282. doi: 10.1038/ncomms14282

Table 7. DFT aided validation for nine randomly selected RP oxides that were predicted to have an NCS ground state structure from ML.

RP oxides DFT ground state NCS ground state (in %) Predicted space groups from ML [irrep label]
ΔED
    as predicted from ML Tree 1 Tree 2 Tree 3 Tree 4 Tree 5  
NaLaHfO4 PInline graphic21m (NCS) 100 Pca21 [Inline graphicInline graphic] P21212 [Inline graphic(η1,η2)] PInline graphic21m [Inline graphic(η1,η1)] Pca21 [Inline graphicInline graphic] P21212 [Inline graphic(η1,η2)] −17.9
                 
NaLaZrO4 PInline graphic21m (NCS) 80 Pca21 [Inline graphicInline graphic] P21212 [Inline graphic(η1,η2)] Pbcm [Inline graphic(0,η1)] Pca21 [Inline graphicInline graphic] P21212 [Inline graphic(η1,η2)] −22.6
                 
NaLaIrO4 (FM) PInline graphic21m (NCS) 100 Pca21 [Inline graphicInline graphic] P21212 [Inline graphic(η1,η2)] PInline graphic21m [Inline graphic(η1,η1)] Pca21 [Inline graphicInline graphic] P21212 [Inline graphic(η1,η2)] +204.6
                 
KLaIrO4 (FM) Pbcm (CS) 80 Pca21 [Inline graphicInline graphic] PInline graphic21m [Inline graphic(η1,η1)] Pca21 [Inline graphicInline graphic] Pca21 [Inline graphicInline graphic] Ibca [P4] +135.4
                 
KBaNbO4 P21 (NCS) 100 Pca21 [Inline graphicInline graphic] PInline graphic21m [Inline graphic(η1,η1)] Pca21 [Inline graphicInline graphic] Pca21 [Inline graphicInline graphic] Pca21 [Inline graphicInline graphic] −832
                 
NaCaTaO4 Pca21 (NCS) 100 Pca21 [Inline graphicInline graphic] Pca21 [Inline graphicInline graphic] PInline graphic21m [Inline graphic(η1,η1)] Pca21 [Inline graphicInline graphic] P21212 [Inline graphic(η1,η2)] +15.9
                 
SrLaInO4 PInline graphic21m (NCS) 100 Pca21 [Inline graphicInline graphic] P21212 [Inline graphic(η1,η2)] P21212 [Inline graphic(η1,η2)] P21212 [Inline graphic(η1,η2)] P21212 [Inline graphic(η1,η2)] +38.9
                 
SrYGaO4 P21 (NCS) 80 P21212 [Inline graphic(η1,η2)] φ P21212 [Inline graphic(η1,η2)] P21212 [Inline graphic(η1,η2)] Pca21 [Inline graphicInline graphic] +26.4
                 
BaLaGaO4 P4/nmm (CS) 60 Pbcm [Inline graphic(0,η1)] P21212 [Inline graphic(η1,η2)] Pbcm [Inline graphic(0,η1)] P21212 [Inline graphic(η1,η2)] P21212 [Inline graphic(η1,η2)] −51.1

CS, centrosymmetric; DFT, density-functional theory; FM, ferromagnetic spin order imposed on the Ir-atom; ML, machine learning; NCS, noncentrosymmetric structures.

Note that in a vast majority of compounds the DFT energy difference between space groups P21212 and PInline graphic21m is of the order of few tenths of meV per atom. Additional details are given in Supplementary Table 3 and Supplementary Note 4. For KBaNbO4, the structure initialized with Pca21 symmetry converged to P21 in our DFT calculations. ΔED (in meV per atom) is the decomposition energy for a chemical reaction given in Supplementary Note 4. Negative and positive values for ΔED indicate that the compound is thermodynamically stable and unstable, respectively.