Convergence of AIMD reference volumes with respect to Brillouin-zone sampling and plane-wave cutoff

Establish the effects of Γ-point-only Brillouin-zone sampling and the 300 eV plane-wave cutoff on the systematically smaller equilibrium volumes obtained in the AIMD reference simulations for the binary and high-entropy refractory carbides by performing explicit convergence tests.

Background

The study finds that the universal machine-learning interatomic potentials generally predict larger lattice parameters than the published AIMD reference data, while static PBE calculations agree closely with one another and yield larger lattice parameters than the AIMD results at 300 K. The authors suggest that the discrepancy may originate partly from the Γ-point-only Brillouin-zone sampling and relatively low 300 eV plane-wave cutoff used in the reference AIMD calculations.

Because the effects of these computational settings have not been quantified, explicit convergence tests are needed to determine whether they account for the smaller AIMD reference volumes and, consequently, part of the apparent underestimation of elastic stiffness by the uMLIPs.

References

The Γ-point-only Brillouin-zone sampling and lower 300 eV plane-wave cutoff used in the reference AIMD simulations are possible contributing factors, although their effects would require explicit convergence tests to establish.

— Benchmarking Universal Machine-Learning Interatomic Potentials for Temperature-Dependent Elasticity of Binary and High-Entropy Refractory Carbides  (2610.11878 - Lebeda et al., 8 Oct 2026) in Section 3.2, “Lattice parameters and thermal expansion”