德国慕尼黑大学MnchenKlo, Simon D.团队报道了Ruddlesden-Popper氮化物的高压合成。相关研究成果于2024年6月25日发表在《自然—化学》。

具有Ruddlesden–Popper型结构的层状钙钛矿对于低维特性至关重要，例如光伏混合碘化物和超导铜氧化物。许多这样的卤化物和氧化物是已知的，但类似的氮化物由于平衡阴离子电荷所需的高阳离子氧化态而难以稳定。

该文报道了三种单层Ruddlesden–Popper（K₂NiF₄型）氮化物Pr₂ReN₄、Nd₂ReN₄和Ce₂TaN₄的高压合成及其结构表征和性能。R₂ReN₄材料（R=Pr和Nd）是金属的，Nd₂ReN₄具有低于15K的铁磁Nd³⁺自旋级。热分解产生具有Peierls型畸变的R₂ReN₃和Re–Re多重键合二聚体链。Ce₂TaN₄具有由八面体倾斜驱动的结构转变，局部畸变和倾斜的磁性Ce³⁺有序证明了二维Ce³⁺/Ce⁴⁺电荷有序相关性。

研究工作表明，可以通过高压合成制备具有不同结构、电子和磁性的Ruddlesden–Popper氮化物，为相关的层状氮化物材料打开了大门。

附：英文原文

Title: High-pressure synthesis of Ruddlesden–Popper nitrides

Author: Weidemann, M., Werhahn, D., Mayer, C., Klger, S., Ritter, C., Manuel, P., Attfield, J. P., Klo, Simon D.

Issue&Volume: 2024-06-25

Abstract: Layered perovskites with Ruddlesden–Popper-type structures are fundamentally important for low-dimensional properties, for example, photovoltaic hybrid iodides and superconducting copper oxides. Many such halides and oxides are known, but analogous nitrides are difficult to stabilize due to the high cation oxidation states required to balance the anion charges. Here we report the high-pressure synthesis of three single-layer Ruddlesden–Popper (K2NiF4 type) nitrides—Pr2ReN4, Nd2ReN4 and Ce2TaN4—along with their structural characterization and properties. The R2ReN4 materials (R=Pr and Nd) are metallic, and Nd2ReN4 has a ferromagnetic Nd3+ spin order below 15K. Thermal decomposition gives R2ReN3 with a Peierls-type distortion and chains of Re–Re multiply bonded dimers. Ce2TaN4 has a structural transition driven by octahedral tilting, with local distortions and canted magnetic Ce3+ order evidencing two-dimensional Ce3+/Ce4+ charge ordering correlations. Our work demonstrates that Ruddlesden–Popper nitrides with varied structural, electronic and magnetic properties can be prepared from high-pressure synthesis, opening the door to related layered nitride materials.

DOI: 10.1038/s41557-024-01558-1

Source: https://www.nature.com/articles/s41557-024-01558-1