ZStar: An automated toolkit for polarization, Born effective charges, dielectric response, and infrared and Raman spectra calculations

Abstract

Born effective charges (BEC) link atomic displacements to polarization, connecting lattice vibrations to 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 calculations across all dimensionalities, including bulk crystals, two-dimensional materials, one-dimensional structures, and molecules, through an integrated workflow spanning input preparation, execution, and response analysis. Berry-phase polarization and real-space dipoles describe responses along periodic and open directions, respectively. Our 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. Reusing the electronic Hamiltonian in the ABACUS+PYATB route enables Raman calculations without additional self-consistent calculations. Reproducible examples and a packaged agent skill support conventional and agent-assisted use. ZStar enables efficient, automated exploration of polarization, BEC, dielectric response, and vibrational spectra across all dimensionalities.