Engineering Interface Magnetism via Defect Control in Complex Oxide Heterostructures

****技术摘要****复合氧化物材料已被证明是发现新的和有用的物理现象的非凡平台。将这些材料组装成人工异质结构提供了大量的进一步机会，既可以发现新科学，也可以应用于铁电RAM、燃料电池和自旋电子学等领域。然而，为了充分利用这些材料，必须解决一些严重的开放性问题，特别是在界面应变和缺陷方面。该项目的目标就是实现这一点，使用钴氧化物作为模型系统来了解应变状态，氧空位形成和排序以及界面磁性/电子输运之间的相互作用。具体的机会包括对氧缺陷的应变控制，以精确地设计界面的磁性和电子特性，以及合成无缺陷材料的可能性，以探索最近理论预测的新物理。这项研究的影响将远远超出它所从事的直接学科，因为它与新兴技术有关，为学生提供了特殊的教育机会，并纳入了代表性不足的群体。通过开发明尼阿波利斯公立学校系统中物质属性模块的互动演示，还将实现与公众的接触，影响数百名8年级学生。****非技术摘要****复合氧化物是由多种金属元素的原子与氧结合形成的，是一组在物理和化学性质上表现出非凡多样性的材料，产生了一些物理学上最重要的发现。最近人们认识到，将这些材料结合到人工结构中，将多种氧化物层压在一起，具有原子级精度，这为在各种应用中充分利用它们的特性提供了一种手段。这些技术包括零启动时间记忆、清洁燃料电池和低功耗高速电子设备。然而，关键的未解决的问题阻碍了这一领域的进展，特别是与缺失氧原子相关的有害缺陷的形成。在这个项目中，一组特定的复杂氧化物材料被用来了解是什么因素控制了这些缺陷的形成和排列，它们对性能的影响，以及我们可以控制它们的方法。最终目标是能够精确控制氧化物界面的电子和磁性行为，以便在各种新设备中充分利用它们的独特性能。这项研究将产生广泛的影响，因为它与新兴技术有关，为学生提供了特殊的教育机会，并纳入了代表性不足的群体。通过开发明尼阿波利斯公立学校系统中物质属性模块的互动演示，还将实现与公众的接触，影响数百名8年级学生。

****Technical Abstract****Complex oxide materials have proven to be an extraordinary platform for discovery of new and useful physical phenomena. Assembling these materials into artificial heterostructures provides a plethora of further opportunities, both for discovery of new science, and for applications in areas such as ferroelectric RAM, fuel cells, and spintronics. However, in order to fully exploit these materials some serious open issues must be resolved, particularly with respect to interfacial strain and defects. The goal of this project is to achieve exactly this, using cobalt oxides as model systems to understand the interplay between strain state, oxygen vacancy formation and ordering, and interface magnetism/electronic transport. Specific opportunities include the use of strain-control over oxygen defects to precisely engineer interfacial magnetic and electronic properties, and the possibility of synthesizing defect-free materials to probe new physics recently predicted by theory. The research will have impact well beyond the immediate disciplines in which it is performed, due to its relevance to emerging technologies, the exceptional educational opportunities provided to students, and inclusion of under-represented groups. Outreach to the public will also be achieved via development of an interactive presentation for the Properties of Matter module in the Minneapolis Public School System, impacting hundreds of 8th grade students. ****Non-Technical Abstract****Complex oxides, formed by bonding atoms of multiple metallic elements with oxygen, are a set of materials that display extraordinary diversity in physical and chemical properties, yielding some of the most important discoveries in physics. The recently recognized ability to incorporate these materials into artificial structures where multiple oxides are laminated together, with atomic-scale precision, provides a means to fully exploit their properties in a wide variety of applications. These include zero boot-up time memory, clean-burning fuel cells, and low power consumption high-speed electronics. However, critical unsolved issues hinder progress in this area, particularly the formation of unwanted defects associated with missing oxygen atoms. In this project a specific set of complex oxide materials are being used to understand what factors control the formation and arrangement of these defects, the influence they have on properties, and the means by which we can control them. The ultimate goal is to be able to precisely control electronic and magnetic behavior at oxide interfaces in order to fully exploit their unique properties in a wide variety of new devices. The research will have broad impact due to its relevance to emerging technologies, the exceptional educational opportunities provided to students, and inclusion of under-represented groups. Outreach to the public will also be achieved via development of an interactive presentation for the Properties of Matter module in the Minneapolis Public School System, impacting hundreds of 8th grade students.