Hybrid-LLM-GNN: integrating large language models and graph neural networks for enhanced materials property prediction

Graph-centric learning has attracted significant interest in materials informatics. Accordingly, a family of graph-based machine learning models, primarily utilizing Graph Neural Networks (GNN), has been developed to provide accurate prediction of material properties. In recent years, Large Language Models (LLM) have revolutionized existing scientific workflows that process text representations, thanks to their exceptional ability to utilize extensive common knowledge for understanding semantics. With the help of automated text representation tools, fine-tuned LLMs have demonstrated competitive prediction accuracy as standalone predictors. In this paper, we propose to integrate the insights from GNNs and LLMs to enhance both prediction accuracy and model interpretability. Inspired by the feature-extraction-based transfer learning study for the GNN model, we introduce a novel framework that extracts and combines GNN and LLM embeddings to predict material properties. In this study, we employed ALIGNN as the GNN model and utilized BERT and MatBERT as the LLM model. We evaluated the proposed framework in cross-property scenarios using 7 properties. We find that the combined feature extraction approach using GNN and LLM outperforms the GNN-only approach in the majority of the cases with up to 25% improvement in accuracy. We conducted model explanation analysis through text erasure to interpret the model predictions by examining the contribution of different parts of the text representation.