i-PI 3.0: A flexible and efficient framework for advanced atomistic simulations

The Journal of Chemical Physics, Journal Year: 2024, Volume and Issue: 161(6)

Published: Aug. 14, 2024

Atomic-scale simulations have progressed tremendously over the past decade, largely thanks to availability of machine-learning interatomic potentials. These potentials combine accuracy electronic structure calculations with ability reach extensive length and time scales. The i-PI package facilitates integrating latest developments in this field advanced modeling techniques a modular software architecture based on inter-process communication through socket interface. choice Python for implementation rapid prototyping but can add computational overhead. In new release, we carefully benchmarked optimized several common simulation scenarios, making such overhead negligible when is used model systems up tens thousands atoms using widely adopted machine learning potentials, as Behler–Parinello, DeePMD, MACE neural networks. We also present features, including an efficient algorithm bosonic fermionic exchange, framework uncertainty quantification be conjunction infrastructure that allows deeper integration electronic-driven simulations, approach simulate coupled photon-nuclear dynamics optical or plasmonic cavities.

Language: Английский

Anisotropic anharmonicity dictates the thermal conductivity of β-Ga2O3

Physical review. B./Physical review. B, Journal Year: 2025, Volume and Issue: 111(9)

Published: March 20, 2025

$\ensuremath{\beta}{\text{-Ga}}_{2}{\text{O}}_{3}$ is a promising material candidate for next-generation high-power devices even as its low thermal conductivity ($\ensuremath{\kappa}$) limits utilization due to an inability sufficiently dissipate heat. Despite the importance of this inherent challenge, significant discrepancy persists between experimental results and computational models regarding anisotropic $\ensuremath{\beta}{\text{-Ga}}_{2}{\text{O}}_{3}$. Specifically, are within error bounds ${\ensuremath{\kappa}}_{100}$ ${\ensuremath{\kappa}}_{001}$ while underpredicting ${\ensuremath{\kappa}}_{010}$, suggesting that bare phonon used in literature missing essential physics related transport. In response, we compute $\ensuremath{\kappa}$ using first principles Peirels-Boltzmann transport equation under different approximations. For simplest model, consider heat carriers be harmonic phonons with scattering rates obtained perturbatively. These then compared those by including renormalization four-phonon scattering. Our show accounting resolves experiment theory. This because leads enhancement caused directionally dependent changes group velocities accompanied general increase lifetime. Owing crucial role these anharmonic interactions accurately describing transport, also explore anharmonicity individual atoms octahedrally coordinated gallium atom most thus likely responsible failure model describe material. Finally, demonstrate atomic anharmonicities could useful metric guide tailoring vibrational properties.

Language: Английский

Transport coefficients from equilibrium molecular dynamics

The Journal of Chemical Physics, Journal Year: 2025, Volume and Issue: 162(6)

Published: Feb. 13, 2025

The determination of transport coefficients through the time-honored Green–Kubo theory linear response and equilibrium molecular dynamics requires significantly longer simulation times than those properties while being further hindered by lack well-established data-analysis techniques to evaluate statistical accuracy results. Leveraging recent advances in spectral analysis current time series associated with trajectories, we introduce a new method estimate full (diagonal as well off-diagonal) Onsager matrix from single model. This approach, based on knowledge distribution Onsager-matrix samples frequency domain, unifies evaluation diagonal (conductivities viscosities) off-diagonal (e.g., thermoelectric) within comprehensive framework, improving reliability coefficient estimation for materials ranging molten salts solid-state electrolytes. We validate this against existing approaches using benchmark data cesium fluoride liquid water conclude our presentation computation various Li3PS4 electrolyte.

Language: Английский