Universal Thermodynamic Interatomic Potentials for Crystalline Materials

2026-08-14

AI Summary

This study addresses the computational inefficiency of ensemble averaging in free energy calculations by proposing Thermodynamic Interatomic Potentials (TIP) and a universal model, UMA. This approach extends static potential energy into a Gibbs free energy model by integrating the quasi-harmonic approximation with molecular dynamics data, leveraging automatic differentiation to enable single-shot evaluation of thermodynamic responses. Consequently, finite-temperature phase stability predictions become as tractable as ground-state calculations. The framework facilitates rapid identification of phase transitions, dynamically stable phases, and alloy miscibility gaps. By bridging the gap between static energetics and finite-temperature thermodynamics, this method significantly enhances both the efficiency and accuracy of high-throughput materials screening and phase diagram prediction, overcoming traditional bottlenecks associated with rigorous free energy computations.

Abstract

Free energies govern solid-state phase stability, yet computational materials discovery still relies largely on ground-state energies because free energy calculations require ensemble averages. We introduce the thermodynamic interatomic potential (TIP), which extends an interatomic potential from its static energy to a thermodynamically consistent Gibbs free energy model, with thermodynamic responses following from temperature and pressure by automatic differentiation. We implement TIP[UMA] using the universal potential UMA, train it on free energies from quasi-harmonic to molecular dynamics fidelity, and calibrate it to higher-resolution calculations or experiment. From a single evaluation, it returns the equation of state of a crystal and locates phase transitions among competing branches, including dynamically stabilized phases. Fine-tuning extends the model to alloy solubility limits and miscibility gaps. TIP makes the free energy as accessible as the potential energy, opening finite-temperature phase stability to high-throughput discovery.

Problem

• Free energy
• Phase stability
• Computational materials discovery
• Interatomic potentials
• High-throughput screening

Innovation

• Thermodynamic Interatomic Potential
• Gibbs Free Energy
• Automatic Differentiation
• Universal Potential
• High-throughput Discovery