Paper Overview
- Field: Machine Learning (ML)
- Authors: Juno Nam, Bowen Deng, Xiaochen Du
- Published: 2026-08-17
- arXiv: 2508.08536
- Problem: Computational materials discovery is bottlenecked by ensemble-average-free-energy calculations, forcing heavy reliance on ground-state energies.
- Method: Thermodynamic Interatomic Potential (TIP) — extends a universal interatomic potential into a thermodynamically consistent Gibbs free energy model with responses obtained via automatic differentiation with respect to temperature and pressure.
- Implementation: TIP[UMA], built on the universal potential UMA.
- Training Data: Free energies spanning quasi-harmonic to molecular dynamics fidelities; calibration to higher-resolution DFT calculations or experiments.
- Capabilities from a Single Evaluation:
- Full equation of state of a crystal.
- Location of phase transitions among competing branches, including dynamically stable phases.
- Extension via Fine-Tuning: Alloy solubility limits and miscibility gaps.
- Impact: Makes finite-temperature Gibbs free energies as accessible as static potential energies, enabling high-throughput computational discovery of phase stability.
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 stable phases. Fine-tuning extends the model to alloy solubility limits and miscibility gaps. TIP makes free energy as easy to access as potential energy, opening the door to high-throughput discovery of finite-temperature phase stability.