Details

Autor(en) / Beteiligte

• Raji, Aravind
• Dong, Zhengang
• Porée, Victor
• Subedi, Alaska
• Li, Xiaoyan
• Mundet, Bernat
• Varbaro, Lucia
• Domínguez, Claribel
• Hadjimichael, Marios
• Feng, Bohan
• Nicolaou, Alessandro
• Rueff, Jean-Pascal
• Li, Danfeng
• Gloter, Alexandre

Titel

Valence-Ordered Thin-Film Nickelate with Tricomponent Nickel Coordination Prepared by Topochemical Reduction

Ist Teil von

• ACS nano, 2024-01, Vol.18 (5), p.4077-4088

Ort / Verlag

American Chemical Society

Erscheinungsjahr

2024

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• The metal-hydride-based "topochemical reduc-tion" process has produced several thermodynamically unstable phases across various transition metal oxide series with unusual crystal structures and nontrivial ground states. Here, by such an oxygen (de-)intercalation method we synthesis a samarium nickelate with ordered nickel valences associated with tri-component coordination configurations. This structure, with a formula of Sm 9 Ni 9 O 22 as revealed by four-dimensional scanning transmission electron microscopy (4D-STEM), emerges from the intricate planes of {303} pc ordered apical oxygen vacancies. X-ray spectroscopy measurements and ab initio calculations show the coexistence of square planar, pyramidal, and octahedral Ni sites with mono-, bi-, and tri-valences. It leads to an intense orbital polarization, charge-ordering, and a ground state with a strong electron localization marked by the disappearance of ligand-hole configuration at low temperature. This nickelate compound provides another example of previously inaccessible materials enabled by topotactic transformations and presents an interesting platform where mixed Ni valence can give rise to exotic phenomena.