2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/22535A lattice generalization of the $(b_{1u}\oplus b_{2g})\otimes b_{3u}$ pseudo-Jahn-Teller model is analyzed within mean-field theory. Ferroelectric or antiferroelectric ground states are found for sufficiently large pseudo-Jahn-Teller coupling.4 pages, 2 figuresCondensed Mattertext