Interplay between spin-orbit coupling and correlation in transition metal materials

过渡金属材料中自旋轨道耦合与相关性之间的相互作用

• 批准号: 249762-2011
• 负责人: Kee, HaeYoung
• 金额: $ 1.24万
• 依托单位: University of Toronto
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2015
• 资助国家: 加拿大
• 起止时间: 2015-01-01 至 2016-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=570719
• 关键词: Interplay; between; spin; orbit; coupling

Transition metal compounds may offer multiple routes to new devices in a wide range of green technologies such as solid oxide fuel cells and lossless power transmission. The promise for these opportunities come from a variety of coexisting or interconnected phenomena that these materials often possess. In particular, transition metal compounds exhibit novel phenomena including multiferroicity, high temperature superconductivity, antiferromagnetism, and ferroelectricity. Despite the potential usefulness and ubiquity, the fundamental mechanisms behind these novel properties are not well understood. Theoretical studies on these systems have so far concentrated on strong interactions between electrons due to the localized nature of d-orbitals of transition metal elements, but did not treat other degrees of freedom such as spin-orbit coupling on an equal footing. For instance, while spin-orbit coupling has been recognized as an essential ingredient in spintronics, especially in semi-conductor materials, the corresponding effect in transition metal compounds has been largely ignored or treated perturbatively. Even though this may be a reasonable practice for 3d-shell transition metal systems, as the mass of transition metal elements become heavier (for example, 5d systems such as Re-, Os-, and Ir-based oxides), the spin-orbit coupling strength increases drastically. Thus, the diversity of collective phenomena discovered in these systems calls for more systematic theoretical studies as to how the interplay between spin-orbit coupling and correlations plays a role in the emergence of novel phases and its more practical applications. The goal of this proposal is to achieve a theoretical understanding of how the combination of spin-orbit coupling and electron-electron interactions determines the collective properties of transition metal compounds. The proposed research will advance our knowledge of fundamental properties of quantum materials and suggest directions to the discovery of new phases of matter. It will also open a new avenue for designing and developing advanced materials to serve in a full array of device applications.

过渡金属化合物可以为各种绿色技术中的新设备提供多种途径，例如固体氧化物燃料电池和无损电力传输。这些机会的希望来自于这些材料通常具有的各种共存或相互关联的现象。 特别是，过渡金属化合物表现出新的现象，包括多铁性，高温超导性，反铁磁性和铁电性。 尽管潜在的有用性和普遍性，这些新特性背后的基本机制还没有得到很好的理解。 迄今为止，对这些系统的理论研究主要集中在由于过渡金属元素d轨道的定域性质而导致的电子之间的强相互作用上，但没有平等地对待其他自由度，如自旋轨道耦合。例如，虽然自旋-轨道耦合已被认为是自旋电子学中的基本成分，特别是在半导体材料中，但过渡金属化合物中的相应效应在很大程度上被忽略或微扰处理。尽管这对于3d-壳过渡金属系统可能是合理的实践，但是随着过渡金属元素的质量变得更重（例如，5d系统，诸如Re-、Os-和Ir-基氧化物），自旋-轨道耦合强度急剧增加。因此，在这些系统中发现的集体现象的多样性要求更系统的理论研究，如何自旋轨道耦合和相关性之间的相互作用在新阶段的出现及其更实际的应用中发挥作用。 该提案的目标是从理论上理解自旋-轨道耦合和电子-电子相互作用的组合如何决定过渡金属化合物的集体性质。拟议中的研究将推进我们对量子材料基本性质的认识，并为发现物质的新阶段指明方向。它还将为设计和开发先进材料开辟一条新的途径，以用于各种设备应用。