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arxiv: 2604.20515 · v1 · submitted 2026-04-22 · ❄️ cond-mat.mtrl-sci

Recognition: unknown

Accurate and Efficient Interatomic Potentials for Dislocations in InP

James Kermode, Richard Beanland, Thomas Hudson, Thomas Rocke

Authors on Pith no claims yet

Pith reviewed 2026-05-10 00:17 UTC · model grok-4.3

classification ❄️ cond-mat.mtrl-sci
keywords interatomic potentialsdislocationsInPIndium Phosphidemachine learning potentialsdensity functional theorymaterial defectssemiconductor modeling
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0 comments X

The pith

Bespoke machine-learned potentials reproduce partial dislocation formation energies in InP to within 4% of DFT.

A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.

The paper trains Atomic Cluster Expansion and MACE interatomic potentials on a new set of DFT calculations built around dislocation core structures and related configurations in Indium Phosphide. These models are tested in a validation suite and shown to match DFT formation energies for partial dislocations far more closely than earlier bespoke potentials or general foundation models. A reader would care because dislocations control plastic deformation and failure in III-V semiconductors used in optoelectronics and high-speed electronics, so better atomistic models directly improve predictions of material reliability under stress. The work also reports that the tailored MACE model runs about five times faster than the compared foundation models while keeping the accuracy gain.

Core claim

A DFT dataset focused on dislocation-relevant atomic arrangements in InP is used to train ACE and MACE models that achieve at most 4% error on partial dislocation formation energies, compared with 18% for the MACE-MPA foundation model and 42-50% for previously published potentials; the custom MACE model delivers this accuracy at roughly five times the evaluation speed of the MP0 and MPA models.

What carries the argument

Atomic Cluster Expansion (ACE) and MACE machine-learned interatomic potentials trained on a dislocation-specific DFT dataset and validated against RSCAN calculations.

If this is right

  • Simulations of dislocation mobility and interactions in InP can now be performed with formation-energy errors below 4% relative to DFT.
  • The fivefold speed-up of the bespoke MACE model enables larger-scale or longer-time simulations than are practical with the slower foundation models.
  • Direct comparison to literature potentials shows that domain-specific training data reduces errors on defect energetics by more than an order of magnitude in this material.
  • The same training and validation workflow can be reused to produce potentials for other defect-driven properties once additional DFT data are added.

Where Pith is reading between the lines

These are editorial extensions of the paper, not claims the author makes directly.

  • The dataset-construction strategy used here could be applied to other compound semiconductors to obtain similarly accurate potentials for their dislocations.
  • Faster potentials open the possibility of coupling atomistic dislocation simulations to continuum models of plastic flow in device-scale structures.
  • If the models also reproduce experimental dislocation velocities, they could reduce reliance on direct DFT for screening doping or alloying effects on InP mechanical behavior.

Load-bearing premise

The new DFT dataset and validation tests include enough of the atomic environments that actually occur during dislocation motion and core reconstruction in InP for the reported energy errors to carry over to dynamic simulations.

What would settle it

If molecular-dynamics runs with these potentials produce dislocation core structures, migration barriers, or velocities that differ substantially from independent RSCAN DFT calculations or from experimental measurements on InP, the accuracy claim would be refuted.

Figures

Figures reproduced from arXiv: 2604.20515 by James Kermode, Richard Beanland, Thomas Hudson, Thomas Rocke.

Figure 1
Figure 1. Figure 1: FIG. 1: Equations of State (EOS) predictions for InP [PITH_FULL_IMAGE:figures/full_fig_p004_1.png] view at source ↗
Figure 2
Figure 2. Figure 2: FIG. 2: Phonon spectrum, compared with experimental [PITH_FULL_IMAGE:figures/full_fig_p004_2.png] view at source ↗
Figure 3
Figure 3. Figure 3: FIG. 3: Comparison of Point Defect Formation Energies [PITH_FULL_IMAGE:figures/full_fig_p005_3.png] view at source ↗
Figure 4
Figure 4. Figure 4: FIG. 4: Indium Interstitial & Vacancy Migration Barriers, as predicted by several potentials. The top left panel [PITH_FULL_IMAGE:figures/full_fig_p006_4.png] view at source ↗
Figure 5
Figure 5. Figure 5: FIG. 5: Phosphorus Interstitial & Vacancy Migration Barriers, as predicted by several potentials. The top left panel [PITH_FULL_IMAGE:figures/full_fig_p007_5.png] view at source ↗
Figure 6
Figure 6. Figure 6: FIG. 6: Comparison of predicted stacking fault barriers for several InP potentials. The four larger panels show the [PITH_FULL_IMAGE:figures/full_fig_p008_6.png] view at source ↗
Figure 7
Figure 7. Figure 7: FIG. 7: Comparison of relaxed dislocation quadrupole [PITH_FULL_IMAGE:figures/full_fig_p009_7.png] view at source ↗
Figure 8
Figure 8. Figure 8: FIG. 8: Migration Barriers for a partial core glide event in the quadrupole. The top panel shows the predicted [PITH_FULL_IMAGE:figures/full_fig_p010_8.png] view at source ↗
read the original abstract

We present Atomic Cluster Expansion (ACE) and MACE models trained on a new dataset of Density Functional Theory (DFT) calculations, constructed for the task of studying the mobility of dislocations in Indium Phosphide (InP). The models are validated in a suite of tests against RSCAN DFT, and compared with previously published potentials from literature. Our new models act as much better surrogates for DFT than the literature models: errors on partial dislocation formation energies are at most 4% for both ACE and MACE, compared with 18% for the MACE-MPA foundation model and 42-50% for earlier bespoke potentials. The bespoke MACE model achieves this accuracy while being around five times faster to evaluate than the MP0 and MPA foundation models.

Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, simulated authors' rebuttal, and a circularity audit. Tearing a paper down is the easy half of reading it; the pith above is the substance, this is the friction.

Referee Report

2 major / 2 minor

Summary. The manuscript presents ACE and MACE interatomic potentials trained on a new DFT dataset for InP, constructed specifically to study dislocation mobility. The models are validated against RSCAN DFT and compared to literature potentials, with the central claim that both achieve at most 4% error on partial-dislocation formation energies (versus 18% for MACE-MPA and 42-50% for earlier bespoke models) while the bespoke MACE model evaluates approximately five times faster than MP0/MPA foundation models.

Significance. If the reported accuracy on formation energies generalizes, the potentials would offer a clear improvement as efficient DFT surrogates for large-scale dislocation simulations in InP, a key semiconductor material. The speed advantage over foundation models is a notable practical strength for molecular-dynamics applications.

major comments (2)
  1. [Abstract] Abstract: the claim that the models are 'constructed for the task of studying the mobility of dislocations' rests on validation limited to static partial-dislocation formation energies. No tests on Peierls barriers, nudged-elastic-band paths, or shear-induced saddle-point configurations are described, which is load-bearing for transferability to mobility and core dynamics.
  2. [Validation suite] Validation suite (results section): the reported error metrics (at most 4%) are given only for equilibrium formation energies; without explicit coverage of high-strain or thermally activated configurations in the training or test sets, the generalization to dislocation glide cannot be assessed from the presented evidence.
minor comments (2)
  1. [Abstract] The abstract and introduction could more explicitly qualify the scope of the validation (static vs. dynamic properties) to avoid overstatement of applicability to mobility studies.
  2. [Results] Table or figure presenting the formation-energy comparisons should include the number of configurations tested and the precise definition of the error metric (e.g., relative to what reference value) for reproducibility.

Simulated Author's Rebuttal

2 responses · 0 unresolved

We thank the referee for their constructive and detailed comments on our manuscript. We have addressed each major point below, clarifying the scope of our validation while acknowledging its limitations. Revisions have been made to the abstract and results section to better align the claims with the presented evidence.

read point-by-point responses
  1. Referee: [Abstract] Abstract: the claim that the models are 'constructed for the task of studying the mobility of dislocations' rests on validation limited to static partial-dislocation formation energies. No tests on Peierls barriers, nudged-elastic-band paths, or shear-induced saddle-point configurations are described, which is load-bearing for transferability to mobility and core dynamics.

    Authors: We appreciate the referee highlighting this distinction. The dataset was constructed with a focus on dislocation core configurations in InP, and the abstract phrasing reflected the broader motivation for developing accurate potentials suitable for large-scale dislocation studies. However, we agree that the validation is restricted to static partial-dislocation formation energies and does not include tests on Peierls barriers, NEB paths, or saddle-point configurations. To address this, we have revised the abstract to state that the models are developed and validated for accurate modeling of dislocation core structures and formation energies, serving as a foundation for subsequent mobility investigations. A new paragraph has been added to the discussion section explicitly noting the absence of dynamic barrier calculations and the need for such tests to confirm transferability to glide processes. revision: partial

  2. Referee: [Validation suite] Validation suite (results section): the reported error metrics (at most 4%) are given only for equilibrium formation energies; without explicit coverage of high-strain or thermally activated configurations in the training or test sets, the generalization to dislocation glide cannot be assessed from the presented evidence.

    Authors: The primary error metrics focus on equilibrium formation energies because these directly assess the potentials' fidelity in reproducing the energetics and structures of partial dislocation cores, which is a critical prerequisite for any dislocation-related simulation. The training set incorporates configurations sampled from dislocation models, which include a range of local atomic environments and moderate strains around the cores. We nevertheless agree that the test suite does not explicitly cover high-strain regimes or thermally activated saddle points, limiting direct claims about generalization to dislocation glide. We have expanded the results section to provide more detail on the strain distributions present in the training data and have inserted a limitations paragraph stating that additional validation on glide barriers would be required to fully assess performance in dynamic mobility contexts. revision: partial

Circularity Check

0 steps flagged

No circularity in derivation or validation chain.

full rationale

The paper constructs a new DFT dataset, trains ACE and MACE interatomic potentials on it, and reports direct numerical errors on held-out partial-dislocation formation energies against independent RSCAN DFT reference calculations. No equations, fitted parameters, or self-citations reduce the reported formation-energy errors to the training inputs by construction; the comparisons are standard out-of-sample validation against external DFT data. The central claim of improved surrogate accuracy therefore rests on empirical test-set performance rather than tautological re-expression of the training data.

Axiom & Free-Parameter Ledger

1 free parameters · 1 axioms · 0 invented entities

The central claim rests on the representativeness of the new DFT dataset for dislocation-relevant configurations and on the assumption that standard ML potential training produces transferable models for defect energetics.

free parameters (1)
  • ACE and MACE model hyperparameters and weights
    Large number of parameters fitted to the custom DFT dataset to reproduce energies and forces.
axioms (1)
  • domain assumption DFT calculations (RSCAN functional) provide sufficiently accurate reference data for training and validation of interatomic potentials.
    Invoked when the paper states the models are validated against RSCAN DFT.

pith-pipeline@v0.9.0 · 5432 in / 1290 out tokens · 43912 ms · 2026-05-10T00:17:48.642847+00:00 · methodology

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Reference graph

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