The roles of nonharmonic damping and spatial correlation of atomic movements in determining the amplitudes and attenuation frequencies of electro-optic coefficients

This dataset contains numerical data and analysis scripts supporting the study “The roles of nonharmonic damping and spatial correlation of atomic movements in determining the amplitudes and attenuation frequencies of electro-optic coefficients.” The study investigates how anharmonic damping and spatially correlated atomic motion govern the magnitude and frequency dependence of the electro-optic response of tetragonal barium titanate (BaTiO₃), using molecular-dynamics simulations with machine-learned interatomic potentials and a Green–Kubo formulation of the electro-optic response.

The data archive includes frequency-dependent electro-optic spectra obtained with PBE- and HSE-based potentials, complex Debye-fit data and fitted attenuation frequencies, and results used to examine the dependence of the response on simulation-cell size and interaction strength. It also contains spatial and time-dependent Ti-displacement correlations, layer-resolved correlation data, collective-mode spectral data, and uncertainty-analysis results. Results from the stochastic self-consistent harmonic approximation (SSCHA) include auxiliary-mode dispersion data, mode-resolved contributions to the static electro-optic response, and electronic, ionic, and total static contributions. These numerical datasets support the figures and analyses in the main article and supplementary material and are provided primarily in CSV and NumPy NPZ formats.

Additional calculation records include an AiiDA archive of optical-tensor calculations and separately exported tensor arrays. An independent validation set for the HSE-based neuroevolution potential (NEP) contains 59 atomic configurations, structure metadata and provenance records, reference and predicted energies and forces, and comparison results resolved by configuration, atomic species, and source.

The accompanying code archive provides Python scripts for extracting electro-optic observables and Ti-displacement quantities from molecular-dynamics trajectories, evaluating Green–Kubo response functions, analyzing trajectory windows, plotting electro-optic spectra, and performing complex Debye fits over 25–5000 GHz to determine attenuation frequencies. The scripts retain study-specific paths and parameters and require adaptation before use. Full molecular-dynamics trajectories, mapping files, and some original fitting inputs are not included; the deposit therefore provides figure-supporting data and analysis code rather than a self-contained package for reproducing all calculations from scratch.