  The recently proposed crystal graph convolutional neural network (CGCNN)
offers a highly versatile and accurate machine learning (ML) framework by
learning material properties directly from graph-like representations of
crystal structures ("crystal graphs"). Here, we develop an improved variant of
the CGCNN model (iCGCNN) that outperforms the original by incorporating
information of the Voronoi tessellated crystal structure, explicit 3-body
correlations of neighboring constituent atoms, and an optimized chemical
representation of interatomic bonds in the crystal graphs. We demonstrate the
accuracy of the improved framework in two distinct illustrations: First, when
trained/validated on 180,000/20,000 density functional theory (DFT) calculated
thermodynamic stability entries taken from the Open Quantum Materials Database
(OQMD) and evaluated on a separate test set of 230,000 entries, iCGCNN achieves
a predictive accuracy that is significantly improved, i.e., 20% higher than
that of the original CGCNN. Second, when used to assist high-throughput search
for materials in the ThCr2Si2 structure-type, iCGCNN exhibited a success rate
of 31% which is 310 times higher than an undirected high-throughput search and
2.4 times higher than that of the original CGCNN. Using both CGCNN and iCGCNN,
we screened 132,600 compounds with elemental decorations of the ThCr2Si2
prototype crystal structure and identified a total of 97 new unique stable
compounds by performing 757 DFT calculations, accelerating the computational
time of the high-throughput search by a factor of 130. Our results suggest that
the iCGCNN can be used to accelerate high-throughput discoveries of new
materials by quickly and accurately identifying crystalline compounds with
properties of interest.
