New transition metal oxychalcogenides

新型过渡金属硫属元素化物

• 批准号: EP/J011533/1
• 负责人: John Evans
• 金额: $ 46.01万
• 依托单位: Durham University
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2012
• 资助国家: 英国
• 起止时间: 2012 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=EP%2FJ011533%2F1
• 关键词: New; transition; metal; oxychalcogenides

In this proposal we request funding to investigate the synthesis, structures and electronic/magnetic properties of a variety of new transition metal oxychalcogenides. These are relatively unusual materials which simultaneously contain an oxide (O2-) and a second chalcogenide (S2-, Se2-, Te2-) anion, as opposed to more commonly found species such as sulfates or sulfites (SO42- and SO32-) in which the chalcogen has a positive formal charge. Mixed anion materials are interesting as they frequently contain transition metals in unusual chemical or electronic environments. This can lead to materials with unexpected and fascinating electronic, magnetic or optical properties. A now-classic example of this was the 2008 discovery by Hosono et al. of 26 K superconductivity (now known at temperatures up to 55 K) in materials derived from a oxypnictide LaOFeAs. Superconductivity in an iron-based system such as this at such high temperatures was unprecedented, entirely unexpected and led to significant world-wide interest. Other interesting mixed anion phases include materials such as LnOCuS (Ln = lanthanide) and La2O2CdSe2, which are rare examples of p-type transparent conductors, and could find a range of applications in display devices.In this research programme we plan work in three main areas. Firstly, we want to tune the electronic properties of a fascinating and unusual family of materials of composition Ln2O2M2OSe2 (Ln = lanthanide, M = transition metal). These are closely related to the superconducting pnictide systems but, in their undoped state, lie on the insulator side of a insulator-to-metal boundary. We plan various approaches to chemically modify them to change their conductivity, ideally towards the superconducting region of the phase diagram, and to understand both their structural and physical properties. Secondly, we aim to extend our recent successes in the preparation of novel materials with the closely related composition Ln2O2MSe2. We again aim to understand, control and exploit their electrical and optical properties. We believe discoveries here will also help understand the pnictide systems. In our final work strand we believe that we can adopt a variety of ideas learned from our work and that of others to prepare new families of materials of general formula (LnOQ)1-xMx and (LnOQ)1-xMQx - what we call "4 Angstrom phases". Our aim is to explore the properties of these new phases. The synthetic side of our work will be supported via a variety of characterisation and theoretical methods. We will apply X-ray and neutron scattering techniques to probe the structures, structural changes and magnetic interactions in the materials. The physical properties of interesting materials (conductivity, magnetism, heat capacity, etc) will be measured using equipment available in Durham. Plane wave density functional theory will be used to help us predict and understand the properties of materials targetted or prepared. We believe this synergic approach will allow rapid and insightful progress.

在本提案中，我们请求资金来研究各种新型过渡金属硫属化物的合成、结构和电子/磁性特性。这些是相对不常见的材料，同时含有氧化物 (O2-) 和第二硫族化物 (S2-、Se2-、Te2-) 阴离子，这与更常见的物质如硫酸盐或亚硫酸盐（SO42- 和 SO32-）不同。其中硫属元素具有正形式电荷。混合阴离子材料很有趣，因为它们在不寻常的化学或电子环境中经常含有过渡金属。这可能会导致材料具有意想不到的、令人着迷的电子、磁性或光学特性。 Hosono 等人 2008 年的发现就是一个现在经典的例子。源自氧磷氮化物 LaOFeAs 的材料具有 26 K 超导性（目前已知温度高达 55 K）。像这样的铁基系统在如此高的温度下的超导性是前所未有的、完全出乎意料的，并引起了全世界的极大兴趣。其他有趣的混合阴离子相包括 LnOCuS（Ln = 镧系元素）和 La2O2CdSe2 等材料，它们是 p 型透明导体的罕见例子，可以在显示设备中找到一系列应用。在本研究计划中，我们计划在三个主要方面开展工作地区。首先，我们想要调整 Ln2O2M2OSe2（Ln = 镧系元素，M = 过渡金属）组成的迷人且不寻常的材料系列的电子特性。它们与超导磷族化物系统密切相关，但在未掺杂状态下，位于绝缘体与金属边界的绝缘体一侧。我们计划采用各种方法对它们进行化学修饰，以改变它们的电导率，最好是朝着相图的超导区域，并了解它们的结构和物理特性。其次，我们的目标是扩展我们最近在制备具有密切相关成分 Ln2O2MSe2 的新型材料方面取得的成功。我们的目标再次是了解、控制和利用它们的电学和光学特性。我们相信这里的发现也将有助于理解磷元素系统。在我们的最后工作中，我们相信我们可以采用从我们的工作和其他人的工作中学到的各种想法来制备通式 (LnOQ)1-xMx 和 (LnOQ)1-xMQx 的新材料系列 - 我们称之为“ 4埃阶段”。我们的目标是探索这些新相的特性。我们工作的合成方面将通过各种表征和理论方法得到支持。我们将应用X射线和中子散射技术来探测材料的结构、结构变化和磁相互作用。有趣材料的物理特性（电导率、磁性、热容等）将使用达勒姆提供的设备进行测量。平面波密度泛函理论将用于帮助我们预测和理解目标或制备的材料的特性。我们相信，这种协同方法将带来快速且富有洞察力的进展。

项目成果

Structural and magnetic characterisation of iron oxyselenides Ce2O2Fe2OSe2 and Nd2O2Fe2OSe2

铁氧硒化物 Ce2O2Fe2OSe2 和 Nd2O2Fe2OSe2 的结构和磁性表征

• DOI: http://dx.10.48550/arxiv.1410.4990
• 发表时间: 2014
• 作者: McCabe E

Structural and magnetic characterization of iron oxyselenides Ce 2 O 2 Fe 2 OSe 2 and Nd 2 O 2 Fe 2 OSe 2

铁氧硒化物 Ce 2 O 2 Fe 2 OSe 2 和 Nd 2 O 2 Fe 2 OSe 2 的结构和磁性表征

• DOI: http://dx.10.1103/physrevb.90.165111
• 发表时间: 2014
• 期刊: Physical Review B
• 影响因子: 3.7
• 作者: McCabe E

Averaging the intensity of many-layered structures for accurate stacking-fault analysis using Rietveld refinement

使用 Rietveld 细化平均多层结构的强度以进行准确的堆垛层错分析

• DOI: http://dx.10.1107/s1600576716013066
• 发表时间: 2016
• 期刊: Journal of Applied Crystallography
• 影响因子: 6.1
• 作者: Coelho A

Infinitely Adaptive Transition-Metal Ordering in Ln2O2MSe2-Type Oxychalcogenides.

Ln2O2MSe2 型硫族化合物中的无限自适应过渡金属排序。

• DOI: http://dx.10.1021/acs.inorgchem.5b00599
• 发表时间: 2015
• 期刊: Inorganic chemistry
• 影响因子: 4.6
• 作者: Ainsworth CM

Synthesis, structural characterization, and physical properties of the new transition metal oxyselenide Ce2O2ZnSe2.

新型过渡金属氧硒化物Ce2O2ZnSe2的合成、结构表征和物理性质。

• DOI: http://dx.10.1021/ic502551n
• 发表时间: 2015
• 期刊: Inorganic chemistry
• 影响因子: 4.6
• 作者: Ainsworth CM