New solid-state materials have been discovered using
various approaches
from atom substitution in density functional theory (DFT) to generative
models in machine learning. Recently, generative models have shown
promising performance in finding new materials. Crystal generation
with deep learning has been applied in various methods to discover
new crystals. However, most generative models can only be applied
to materials with specific elements or generate structures with random
compositions. In this work, we developed a model that can generate
crystals with desired compositions based on a crystal diffusion variational
autoencoder. We generated crystal structures for 14 compositions of
three types of materials in different applications. The generated
structures were further stabilized using DFT calculations. We found
the most stable structures in the existing database for all but one
composition, even though eight compositions among them were not in
the data set trained in a crystal diffusion variational autoencoder.
This substantiates the prospect of the generation of an extensive
range of compositions. Finally, 205 unique new crystal materials with
energy above hull <100 meV/atom were generated. Moreover, we compared
the average formation energy of the crystals generated from five compositions,
two of which were hypothetical, with that of traditional methods like
atom substitution and a generative model. The generated structures
had lower formation energy than those of other models, except for
one composition. These results demonstrate that our approach can be
applied stably in various fields to design stable inorganic materials
based on machine learning.