Aberrant electronic and structural alterations in pressure tuned perovskite NaOsO3

Abstract

The perovskite NaOsO3 has a metal–insulator transition at temperature 410 K, which is delicate, intriguing, and provokes a lot of debate on its nature. Our combined electrical resistance, Raman, and synchrotron x-ray diffraction experiments show that the insulating ground state in this osmate endures under high pressure up to at least 35 GPa. In this pressure range, compression reveals hidden hysteretic resistance properties with a transient metallic state near 200 K, manifested three electronic character anomalies (at 1.7, 9.0, and 25.5 GPa), and a structural transition to the singular polar phase (at ~18 GPa). We distinguish NaOsO3 from the regular crystallographic behavior of perovskites, though the electrical specificities resemble iridates and nickelates. The theoretical first-principle band structure and lattice dynamics calculations demonstrate that the magnetically itinerant Lifshitz-type mechanism with spin–orbit and spin–phonon interactions is responsible for these pressure-induced changes. Our findings provide another new playground for the emergence of new states in 5d materials by using high-pressure methods.

Probing the Influence of Defects, Hydration, and Composition on Prussian Blue Analogues with Pressure

“…By way of comparison, pressure-induced polarity is known for a handful of oxide perovskites, resulting from octahedral deformations upon compression. 85 − 87 Group theory shows that out-of-phase tilts (“–”) are likely to give polar space groups when combined with the alternating A-site cation order. 45 , 88 , 89 For example, a – a – a – tilts of a cation-ordered AMM′(CN) 6 compound would yield R 3 symmetry.…”

“…For RbMnCo-III, the pressure-induced a – a – c + tilts reduce the symmetry to the polar space group Pn . By way of comparison, pressure-induced polarity is known for a handful of oxide perovskites, resulting from octahedral deformations upon compression. − Group theory shows that out-of-phase tilts (“–”) are likely to give polar space groups when combined with the alternating A-site cation order. ,, For example, a – a – a – tilts of a cation-ordered AMM′(CN) 6 compound would yield R 3 symmetry. It may be possible to change the direction of the polarization by altering the direction of the tilt, and thereby generating a ferroelectric material, as in certain Ruddlesden–Popper oxides. , This prospect of stimuli-induced polarity motivates further study into the tilt transitions of cation-ordered Prussian blue analogues.…”