Correlated perovskite nickelates with valence variable rare-earth compositions

Research Advances in Rare Earth Oxide‐Based Catalysts for Soot Combustion

“…In this structure, the cation at the A site typically consists of a rare earth or alkaline earth element. [76] It is 12-coordinated with oxygen atoms and resides within a cavity formed by octahedra.…”

Revealing the Role of the Tetragonal Distortion in the Metal–Insulator Transition of Co- and Fe-Doped NiS

“…From the above results, it can be seen that the magnitude of LT MIT (σ Met – σ Ins ) is critical to achieve a high regulation rate in κ. In Figure b, the LT MIT (σ Met – σ Ins ) is summarized for the NiS material herein, compared with the existing family of MIT materials, and plotted as a function of T MIT . − It can be seen that the NiS is the only promising candidate to achieve a synchronized switch in thermal conductivity to MIT, as far as we were concerned. In contrast, the variation in κ C across MIT is not comparable to their κ Ins for most of the existing MIT oxides (e.g., Re NiO 3 , Ca n +1 Ru n O 3 n +1 and Nd 0.5 Sr 0.5 MnO 3 ), because of their low conductivity, even at the metallic phase.…”

In Situ High-Pressure Correlated Transportation of Heavy Rare-Earth Perovskite Nickelates as Batch Synthesized within Eutectic Molten Salts at MPa-pO2

“…3,7 An overwhelming advantage in the MIT functionality of ReNiO 3 is the broad adjustability in their T MIT continuously within a wide temperature range of 100−600 K by simply adjusting the composition of Re. 8,9 A smaller ionic radius of Re distorts the NiO 6 more, which reduces the orbital overlapping between the Ni-3d and O-2p and results in a more stable insulating phase with higher T MIT . 2,4,8,9 Apart from the above band gap regulations, the electronic transportation properties of ReNiO 3 can be more directly switched among multiple electronic states via Mottronic orbital filling control.…”

“…Breaking the thermodynamic restriction and establishing the metastable or unstable electronic phases within electron-correlated semiconductors open up a new paradigm to the exploration of new material functionalities and device applications beyond the conventional . As a representative metastable perovskite, the rare-earth nickelates ( Re NiO 3 ) exhibit an extra-ordinarily complex electrical phase diagram and multiple electronic phase transitions, originating from the high tolerance in manipulating its Ni-3d/O-2p orbital configurations via their NiO 6 octahedron. − The charge disproportionation (antidisproportionation) associated with Ni 3+ t 2 g 6 e g 1 ↔ Ni 2+ t 2 g 6 e g 2 triggered via critical temperatures ( T MIT ) enables the metal-to-insulator transition (MIT) of Re NiO 3 . , An overwhelming advantage in the MIT functionality of Re NiO 3 is the broad adjustability in their T MIT continuously within a wide temperature range of 100–600 K by simply adjusting the composition of Re . , A smaller ionic radius of Re distorts the NiO 6 more, which reduces the orbital overlapping between the Ni-3d and O-2p and results in a more stable insulating phase with higher T MIT . ,,, Apart from the above band gap regulations, the electronic transportation properties of Re NiO 3 can be more directly switched among multiple electronic states via Mottronic orbital filling control. ,,, For example, the d-orbital occupancy within Re NiO 3 can be increased from Ni 3±Δ t 2 g 6 e g 1±Δ (or Ni 3+ t 2 g 6 e g 1 ) to Ni 2+ t 2 g 6 e g 2 via reversable hydrogenation that triggers strong electron localization, , while a superconductive phase associated with the Ni 1+ t 2 g 6 e g 3 can be even formed via heavier hydrogenation. , These recent discoveries extend the fundamental vision in the field of condensed matter physics and also enrich new electronic applications, such as correlated electronics for artificial intelligence, , ocean current electric field sensor, correlated electronics for energy conversion, and biosensing …”

“…8,9 A smaller ionic radius of Re distorts the NiO 6 more, which reduces the orbital overlapping between the Ni-3d and O-2p and results in a more stable insulating phase with higher T MIT . 2,4,8,9 Apart from the above band gap regulations, the electronic transportation properties of ReNiO 3 can be more directly switched among multiple electronic states via Mottronic orbital filling control. 3,7,10,11 For example, the d-orbital occupancy within ReNiO 3 can be increased from Ni 3±Δ t 2g 6 e g 1±Δ (or Ni 3+ t 2g 6 e g 1 ) to Ni 2+ t 2g 6 e g 2 via reversable hydrogenation that triggers strong electron localization, 3,7 while a superconductive phase associated with the Ni 1+ t 2g 6 e g 3 can be even formed via heavier hydrogenation.…”