Machine learning unveils composition-property relationships in chalcogenide glasses

TL;DR

This study uses machine learning to analyze and interpret the relationships between composition and properties in chalcogenide glasses, enabling better design of materials with desired functionalities.

Contribution

It introduces predictive models and interpretability methods for composition-property relationships in chalcogenide glasses, aiding material design.

Findings

Key elements like Ge, Ga, Se, and others significantly influence properties.

Models accurately predict glass transition temperature, Young's modulus, CTE, and refractive index.

Interpretability reveals elemental impacts on properties.

Abstract

Due to their unique optical and electronic functionalities, chalcogenide glasses are materials of choice for numerous microelectronic and photonic devices. However, to extend the range of compositions and applications, profound knowledge about composition-property relationships is necessary. To this end, we collected a large quantity of composition-property data on chalcogenide glasses from SciGlass database regarding glass transition temperature ($T_g$), Young's modulus ($E$), coefficient of thermal expansion (CTE), and refractive index ($n_D$). With these data, we induced predictive models using three machine learning algorithms: Random Forest, K-nearest Neighbors, and Classification and Regression Trees. Finally, the induced models were interpreted by computing the SHAP (SHapley Additive exPlanations) values of the chemical features, which revealed the key elements that significantly impacted the tested properties and quantified their impact. For instance, Ge and Ga increase $T_g$ and $E$ and decrease CTE (three properties that depend on bond strength), whereas Se has the opposite effect. Te, As, Tl, and Sb increase $n_D$ (which strongly depends on polarizability), whereas S, Ge, and P diminish it. Knowledge about the effect of each element on the glass properties is precious for semi-empirical compositional development trials or simulation-driven formulations. The induced models can be used to design novel chalcogenide glasses with required combinations of properties.