Emergent Properties of Highly Correlated Electronic Systems

高度相关电子系统的涌现特性

• 批准号: 0758356
• 负责人: Steven Kivelson
• 金额: $ 42万
• 依托单位: Stanford University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-10-01 至 2012-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0758356&HistoricalAwards=false
• 关键词: Emergent; Properties; Highly; Correlated; Electronic

TECHNICAL SUMMARY:This award supports research and education on emergent properties of highly correlated electronic systems. The main thrust of the research undertaken here is the effort at theoretical characterization of qualitatively new behaviors of interacting electrons (i.e. new states of matter) as well as new regimes of parameters in which familiar states of matter behave in new and different ways. In addition, some of the research explores qualitatively the relation between the microscopic interactions between electrons and the effective parameters that control the macroscopic behavior of solids.The search for new states of matter continues an ongoing effort by the PI in the theory of ''electronic liquid crystals.'' This work is based on an analogy between classical liquid crystals and corresponding phases of strongly interacting electrons. Electronic liquid crystals are quantum states with behaviors intermediate between a Fermi liquid and a Wigner crystal. Examples of such states have recently been observed experimentally: the anisotropic states (quantum Hall nematics) that are seen in high mobility quantum Hall devices and the metamagnetic nematic phase that has recently been identified in Sr3Ru2O7. The more microscopic issues to be addressed involve the physics of the superconducting Tc. A number of questions are addressed theoretically. What is it about superconductivity that causes transition temperatures, generally, to be so low, while other orders, such as ferromagnetism, frequently onset at much higher temperatures? Why is there, in the cuprate high temperature superconductors, an ''optimal'' doping at which Tc is maximal ? what is there an excess of in ''overdoped'' cuprates? Are there optimal mesoscale structures for superconductivity, structures that enhance the strength of the electron pairing without too strongly suppressing the superfluid stiffness? The research also seeks to interpret the importance of evidence of wide-spread mesoscale inhomogeneities in the cuprates ? both self-organized (i.e. stripes) and nucleated by disorder. The research is motivated by a need to clarify whether these observations are complicating details or essential to the mechanism of high temperature superconductivity.The effort undertaken has broader impacts with both scientific and educational consequences. Scientifically, there is impact in extending the understanding of the origins of high temperature superconductivity because that opens new theoretical opportunities as well as providing better ability to design materials with this highly desirable property. Involving students and postdoctoral researchers in the diverse problems and theoretical techniques used provides an exceptional training for talented young people. Past students and postdoctoral researchers have gone on to university faculty positions and their own careers in teaching and research and some have found successful positions in high tech companies and a variety of other fields outside of mainstream physics.NONTECHNICAL SUMMARY:This award supports research and education on exotic properties and unexplained electronic states of unusual materials. The broad thrust of the research undertaken here is the theoretical characterization of qualitatively new behaviors and new states of matter as well as investigating how familiar forms matter can be made to behave in new and different ways. This research explores these unusual states of matter by looking at the behavior of electrons and the microscopic level of the atoms that make up the material and then connecting those behaviors with the large scale properties which are seen in the material as a solid whole.The search for new states of matter continues an ongoing effort by the PI in the theory of ''electronic liquid crystals.'' This work develops theories of why some materials have electrons that are not just quiescently distributed more or less uniformly but which instead group together in various patterns.The issues to be addressed also involve the physics of the superconducting materials, those which can conduct electricity with no resistance and thus no waste of energy. The questions are quite basic. What is it about superconductivity that causes working temperatures, generally, to be so low? Why is there, in some high temperature superconductors, an ''optimal'' composition at which the working temperature is highest? Are there optimal ways of creating structures for superconductivity, structures that enhance performance? The research is motivated by a need to clarify which experimental observations are complicating details and which are essential clue to discovering to the mechanism needed to explain high temperature superconductivity.The effort undertaken has broader impacts with both scientific and educational consequences. Scientifically, there is impact in extending the understanding of the origins of high temperature superconductivity because that opens new theoretical opportunities as well as providing better ability to design materials with this highly desirable property. Involving students and postdoctoral researchers in the diverse problems and theoretical techniques used provides an exceptional training for talented young people. Past students and postdoctoral researchers have gone on to university faculty positions and their own careers in teaching and research and some have found successful positions in high tech companies and a variety of other fields outside of mainstream physics.

技术摘要：该奖项支持有关高度相关电子系统新兴属性的研究和教育。这里进行的研究的主要目的是努力在互动电子的定性新行为（即物质的新状态）以及新的参数制度的理论表征上，其中熟悉的物质状态以新的和不同的方式行事。此外，某些研究还定性地探索了电子之间的微观相互作用与控制固体宏观行为的有效参数之间的关系。对物质的搜索持续的搜索持续了PI在“电子液体晶体”理论中的持续努力。“这项工作是基于古典液体晶体和相应相互作用的相互作用层之间的类似学。 电子液晶是量子状态，其行为中间是费米液体和wigner晶体之间的。最近已经通过实验观察到了此类状态的例子：在高迁移率量子霍尔设备中可见的各向异性状态（量子霍尔列明）和最近在SR3RU2O7中鉴定出的元磁性nematic阶段。要解决的微观问题涉及超导TC的物理。从理论上解决了许多问题。 超导性使过渡温度通常如此低的超导性是什么，而其他秩序（例如铁磁性）经常在更高的温度下发作？为什么在Cuprate高温超导体中有“最佳”兴奋剂在哪个TC最大的兴奋剂中？ “超额”铜矿中有什么过多的？是否有最佳的中尺度结构可用于超导性，可以增强电子配对强度而不会过分抑制超流体刚度的结构？该研究还试图解释丘比特人中广泛中尺度不均匀性的证据的重要性吗？自组织（即条纹）都被无序成核。这项研究的激励是需要澄清这些观察结果是否使细节复杂化或对高温超导性机制必不可少。从科学上讲，扩展对高温超导性的起源的理解有影响，因为这开辟了新的理论机会，并提供了更好地设计材料的能力。 参与不同问题和理论技术的学生和博士后研究人员为才华横溢的年轻人提供了出色的培训。过去的学生和博士后研究人员一直从事大学教师职位以及他们自己的教学和研究职业，有些人在高科技公司和主流物理以外的许多其他领域中获得了成功的职位。该奖项支持外来物业的研究和教育，以及对不寻常材料的未解释的电子状态的研究和教育。这里进行的研究的广泛作用是定性新行为和物质的新状态的理论表征，以及研究如何使熟悉的形式以新的和不同的方式行事。这项研究通过查看电子的行为以及组成材料的原子的微观水平，然后将这些行为与大规模的属性联系起来，这些材料在材料中被视为固体整体，对物质的搜索持续努力，这些材料不再是“电子液体液体的理论”，这些材料持续不断地努力。统一但要以各种模式将其分组在一起。要解决的问题还涉及超导材料的物理，这些材料可以无电，因此没有浪费能量的材料。问题很基本。 超导性使工作温度通常如此之低的是什么？为什么在某些高温超导体中，工作温度最高的“最佳”组成？是否有最佳的方法来创建超导性的结构，增强性能的结构？这项研究的激励是需要阐明哪些实验观察结果使细节复杂化，哪些是发现高温超导性所需的机制的重要线索。所进行的努力对科学和教育后果产生了更大的影响。从科学上讲，扩展对高温超导性的起源的理解有影响，因为这开辟了新的理论机会，并提供了更好地设计材料的能力。 参与不同问题和理论技术的学生和博士后研究人员为才华横溢的年轻人提供了出色的培训。过去的学生和博士后研究人员一直从事大学教师职位以及他们自己的教学和研究职业，有些人在高科技公司和主流物理以外的其他各种领域中找到了成功的职位。