Latent Conservative Objective Models for Data-Driven Crystal Structure Prediction

TL;DR

This paper introduces LCOMs, a data-driven method using conservative surrogate models and graph auto-encoders to efficiently predict crystal structures, achieving comparable success rates to current methods with much lower computational cost.

Contribution

The paper presents a novel latent conservative objective model (LCOMs) that combines graph auto-encoders and conservative surrogate modeling for efficient crystal structure prediction.

Findings

Achieves similar success rates to state-of-the-art methods.

Significantly reduces computational cost.

Effectively handles non-Euclidean crystal structure space.

Abstract

In computational chemistry, crystal structure prediction (CSP) is an optimization problem that involves discovering the lowest energy stable crystal structure for a given chemical formula. This problem is challenging as it requires discovering globally optimal designs with the lowest energies on complex manifolds. One approach to tackle this problem involves building simulators based on density functional theory (DFT) followed by running search in simulation, but these simulators are painfully slow. In this paper, we study present and study an alternate, data-driven approach to crystal structure prediction: instead of directly searching for the most stable structures in simulation, we train a surrogate model of the crystal formation energy from a database of existing crystal structures, and then optimize this model with respect to the parameters of the crystal structure. This surrogate model is trained to be conservative so as to prevent exploitation of its errors by the optimizer. To handle optimization in the non-Euclidean space of crystal structures, we first utilize a state-of-the-art graph diffusion auto-encoder (CD-VAE) to convert a crystal structure into a vector-based search space and then optimize a conservative surrogate model of the crystal energy, trained on top of this vector representation. We show that our approach, dubbed LCOMs (latent conservative objective models), performs comparably to the best current approaches in terms of success rate of structure prediction, while also drastically reducing computational cost.