ZStar: A unified toolkit for polarization, Born effective charges, dielectric and piezoelectric responses, and infrared and Raman spectra
Year: 2026
Type: preprint
Abstract: Born effective charge (BEC) tensors link atomic displacements to polarization, thereby connecting lattice vibrations with dielectric response and infrared activity. We present ZStar, an open-source Python toolkit that automates calculations of polarization, BEC, phonons, static and frequency-dependent dielectric response, and infrared and Raman spectra. ZStar supports bulk crystals, two-dimensional materials, one-dimensional structures, and molecules through an integrated workflow for input preparation, execution, and response analysis. Berry-phase polarization and real-space dipoles describe responses along periodic and open directions, respectively. Its unified, symmetry-adapted finite-displacement framework jointly determines BEC and zone-center force constants from the same calculations, improving computational efficiency while preserving numerical accuracy. Strain-response calculations further provide proper piezoelectric coefficients and their internal-relaxation contributions for bulk crystals. In the ABACUS+PYATB route, electronic Hamiltonian data are reused to obtain Raman response without additional self-consistent calculations. Native response implementations from VASP and CP2K are also integrated. Matched infrared/Raman benchmarks against the implemented separate workflows achieve speedups of up to 8.4. An accompanying agent skill provides an agent-friendly interface for workflow integration. ZStar therefore offers an efficient and automated route for exploring polarization, BEC, dielectric and piezoelectric responses, and vibrational spectra across different material dimensionalities.
Source: arXiv (Cornell University)
Language: English
Subfield: Atomic and Molecular Physics, and Optics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
Award: G6202851818
OpenAlex ID: W7213424480