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Sr3Ru2O7: Quantum Nematic Fluid, Vector Magnetic Field Tuning and Spectroscopic Imaging Scanning Tunneling Microscopy

Sr3Ru2O7：量子向列流体、矢量磁场调谐和光谱成像扫描隧道显微镜

基本信息

批准号：
EP/F044704/1
负责人：
Andy MacKenzie
金额：
$ 155.09万
依托单位：
University of St Andrews
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2009
资助国家：
英国
起止时间：
2009 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=EP%2FF044704%2F1
关键词：
Sr3Ru2O7 Quantum Nematic Fluid Vector

项目摘要

It has long been known that if you take a collection of particles that feel strong mutual forces and set things up just right, they can form into intriguing and beautiful patterns. Desk toys and children's games using magnetic iron filings as the particles hint at what is possible, while more recently it has been possible to observe rich patterning in liquid crystals using more or less standard optical microscopy. At the forefront of modern research into interacting particles is the study of so-called 'correlated electrons' in some special metals. Here, the interactions are the result of combining electromagnetic forces with a subtle quantum mechanical force known as the 'Pauli' or 'exchange' force. A rich hierachy of pattern formation, sometimes called 'quantum self-organisation' can be imagined in such materials. However, imagining effects like these is much easier than actually discovering and observing them, because they are extremely fragile. To observe them, we need materials that are purer than anything that could be grown even a decade ago, temperatures within a few degrees of absolute zero (-273 degrees celsius) and microscopes that are hundreds of millions of times more powerful than optical ones.Very recently, we have been able to deduce the existence of such quantum mechanical patterning in a special oxide metal, Sr3Ru2O7. To even get this far, we had to work for eight years to grow the highest quality crystals in the world of it. We now have a unique opportunity to investigate and understand exactly how the quantum self-organisation takes place. To profit from this, we have conceived a major research project. First, we have designed a special 'vector magnet' which can produce an enormous magnetic field aligned along any direction that we define, under computer automated control. No magnet of our required specification has ever been built before, but calculations in collaboration with a specialist company show that it can be done. Using this magnet we will be able to map out the properties of the new phenomena, and optimise the conditions for them to occur.As well as helping us to understand something completely new, this study will be combined with work using a second unique piece of equipment, a Spectroscopic Imaging Scanning Tunneling Microscope (SI-STM). This instrument, built by the group of one of us (Seamus Davis), can image the patterns made by electrons with almost unimaginable resolution. It is sensitive to distances much less than the diameter of a single atom, and can yield information that is highly relevant to the new physics that we will study but cannot be obtained by any other experimental technique. Very few materials have good enough surfaces to be studied using SI-STM, but we have established that Sr3Ru2O7 is ideal by performing a 12 month feasibility study.In performing the research that we propose, we will answer some fundamental questions about the 'quantum many-body problem', one of the most important in modern physics, AND advance instrumentation technology (extending the existing SI-STM and building a new one). One might argue that these rewards are sufficient in their own right, but they are not the only reason for doing research like this. In the long term, continuing to advance the electronic technologies that underpin computation and data storage will require us to work with correlated electron materials that are the subject of today's fundamental research. Understanding self-organisation and patterning of the electrons themselves is going to be vital to that larger quest. This is especially true in materials like Sr3Ru2O7 because they are part of a large family of transition metal oxides which are chemically similar and have the promise, long-term, of being linked together to form a technology based on a far richer set of basic physical properties than is available using today's semiconductors.

人们早就知道，如果你收集一组能够感受到强大相互作用力的粒子，并将它们设置得恰到好处，它们就可以形成有趣而美丽的图案。使用磁性铁屑作为粒子的桌面玩具和儿童游戏暗示了什么是可能的，而最近已经可以使用或多或少的标准光学显微镜观察液晶中的丰富图案。现代研究相互作用粒子的最前沿是研究某些特殊金属中所谓的“关联电子”。在这里，相互作用是电磁力与称为“泡利”或“交换”力的微妙量子力学力相结合的结果。在这种材料中，可以想象出一种丰富的模式形成层次，有时被称为“量子自组织”。然而，想象这样的效果比实际发现和观察它们要容易得多，因为它们非常脆弱。为了观察它们，我们需要比十年前生长的任何东西都更纯净的材料，温度在绝对零度（-273摄氏度）以内，显微镜的功能比光学显微镜强数亿倍。最近，我们已经能够推断出这种量子力学图案在一种特殊的氧化物金属Sr 3Ru 2 O 7中的存在。为了走到这一步，我们必须工作八年才能生长出世界上最高质量的晶体。我们现在有一个独特的机会来研究和准确了解量子自组织是如何发生的。为了从中获益，我们构思了一个重大的研究项目。首先，我们设计了一个特殊的“矢量磁铁”，它可以产生一个巨大的磁场，在计算机自动控制下，沿着我们定义的任何方向沿着。以前从未制造过符合我们要求规格的磁体，但与专业公司合作的计算表明可以做到。使用这种磁铁，我们将能够绘制出新现象的特性，并优化它们发生的条件。除了帮助我们了解全新的东西，这项研究还将与使用第二种独特设备的工作相结合，即光谱成像扫描隧道显微镜（SI-STM）。这个仪器是由我们中的一个人（谢默斯·戴维斯）的小组建造的，它可以以几乎难以想象的分辨率成像电子形成的图案。它对远小于单个原子直径的距离敏感，并且可以产生与我们将要研究的新物理学高度相关的信息，但不能通过任何其他实验技术获得。很少有材料有足够好的表面可以用SI-STM进行研究，但我们已经确定Sr 3Ru 2 O 7是理想的，通过执行12个月的可行性研究。在执行我们提出的研究中，我们将回答一些关于“量子多体问题”的基本问题，现代物理学中最重要的问题之一，以及先进的仪器技术（扩展现有的SI-STM并建立一个新的）。有人可能会说，这些奖励本身就足够了，但它们并不是做这样的研究的唯一原因。从长远来看，继续推进支撑计算和数据存储的电子技术将要求我们使用相关电子材料，这是当今基础研究的主题。理解电子自身的自组织和模式对于更大的探索至关重要。在Sr 3Ru 2 O 7这样的材料中尤其如此，因为它们是化学上相似的过渡金属氧化物大家族的一部分，并且有希望长期连接在一起，形成一种基于比使用今天的半导体更丰富的基本物理特性的技术。