Combined theoretical and experimental study of the low-temperature properties of BaZrO 3

摘要: Low temperature properties of ${\mathrm{BaZrO}}_{3}$ are revealed by combining experimental techniques (x-ray diffraction, neutron scattering and dielectric measurements) with theoretical first-principles-based methods (total energy linear response calculations within density functional theory, effective Hamiltonian approaches without zero-point vibrations). Unlike most the perovskite systems, does not undergo any (long-range-order) structural phase transition thus remains cubic paraelectric down to 2 K, even when neglecting vibrations. On other hand, these latter pure quantum effects lead a negligible thermal dependency lattice parameter below $\ensuremath{\simeq}40\phantom{\rule{0.3em}{0ex}}\mathrm{K}$. They also affect permittivity inducing an overall saturation real part response, for temperatures Two fine structures in part, as well imaginary further observed around 50--65 K 15 respectively. Microscopic origins (e.g., unavoidable defects oxygen octahedra rotation occurring at local scale) such anomalies suggested. Finally, possible reasons facts that some have been previously reported better studied ${\mathrm{KTaO}}_{3}$ ${\mathrm{SrTiO}}_{3}$ incipient ferroelectrics discussed.