A Strange Pattern in the Way Matter Composes Itself
An analysis of a vast database of compounds has revealed a curious repeating pattern in the way matter composes itself. Of more than 80,000 electronic structures of experimental and predicted materials studied, a whopping 60 percent have a basic structural unit based on a multiple of four.
The majority of materials in two databases – the Materials Project database and the Materials Cloud 3-dimensional crystal structures ‘source’ database – have primitive unit cells (the smallest possible unit that repeats within a crystal structure) based on multiples of four. This was concerning because theoretically all structure types should be equally represented in these databases.
The research team ruled out obvious errors, such as flaws in the software used to ‘primitivize’ the unit cells. They also investigated whether the pattern was due to specific elements or properties of the compounds, but no clear correlations were found.
The team then developed a more powerful algorithm to analyze the data. The algorithm grouped the compounds together according to similarities in their atomic properties, but no discernible pattern emerged.
However, when the team ran the data through machine learning algorithms, the output results predicted whether or not a compound would obey the rule of four with up to 87 percent accuracy. This suggests that there may be something that we’re missing about the rule of four compounds that could help explain what produces the pattern.
The research team’s findings suggest that, with ever more powerful computational techniques, we might be able to start making some fascinating headway in understanding the patterns in materials and predicting their properties.
