Local Moment and Heavy Fermion Physics

局域矩和重费米子物理

• 批准号: 0907179
• 负责人: Piers Coleman
• 金额: $ 33万
• 依托单位: Rutgers University New Brunswick
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-09-15 至 2014-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0907179&HistoricalAwards=false
• 关键词: Local; Moment; Heavy; Fermion; Physics

TECHNICAL SUMMARYThis award supports theoretical research and education on heavy electron materials and local moment physics. The new concepts required to understand these low-energy materials, will, in many cases scale up in energy and temperature to describe related phenomenon in transition Metal materials, such as copper and iron-based superconductors. Many of the key questions in this area touch upon issues of fundamental importance, such as the physics of quantum criticality, mechanisms of anisotropic superconductivity, and the origins of non-Fermi liquid behavior. Motivated by the discovery of two new and unusual heavy fermion superconductors, the PI will apply a new type of large-N expansion for heavy electron superconductivity that he has recently developed. Fresh insights in heavy electron quantum criticality and the discovery of a Kondo spin liquid material inspire the PI to embark on a new set of investigations into the phase diagram of the Kondo lattice. A magnetically tuned critical end point in a multiferroic oxide has recently been discovered. The PI will pursue a new research program to study field-tuned quantum criticality in multiferroic materials.Research into the various aspects of "hard condensed matter physics" plays an essential driving role in both the development of new physics concepts, and new ideas for materials of the future. For example, the remarkable tendency of quantum critical points to nucleate superconductivity and other new phases of matter is of great interest to materials development; on the other hand, the new universality classes of quantum phase transition are of great fundamental interest and, like their classical predecessors in statistical mechanics, may enjoy generalization and future application in the realm of cosmology and particle physics. This is wonderful area for students to learn the advanced methods of theoretical physics, while maintaining an intimate contact with experimental physics and real materials.The PI is strongly committed to diversity in physics, with a long record of support for women in physics. Two women graduate students are currently working in his group. NON-TECHNICAL SUMMARYThis award supports theoretical research and education on a class of materials known as heavy electron materials. The interplay of electrons in itinerant quantum states and quantum states localized around a rare-earth or actinide atom leads to an unusual metallic state with properties that are consistent with the textbooks. The properties of these materials are further complicated by the existence of quantum phase transitions - phase transitions that occur at the absolute zero of temperature but with a powerful influence that can be felt over a range of temperature. The PI will build on and use a promising new method that he has developed to gain insight into two recently discovered materials in this class that are superconductors and into heavy electron materials more generally. The PI will also study the superconducting states of these materials. The PI will further explore the role quantum phase transitions play in newly discovered multiferroic materials which are a promising class of materials for future electronic devices. The study of the superconducting states and the unusual metallic states which give way to superconductivity contributes to the intellectual foundations of materials research and superconductivity. This knowledge may lead to harnessing the ability of superconductors to carry electric current with no to very low power dissipation in a practical way leading to significant energy savings. The PI is strongly committed to diversity in physics, with a long record of support for women in physics. Two women graduate students are currently working in his group.

技术摘要该奖项支持重电子材料和局域矩物理的理论研究和教育。在许多情况下，理解这些低能材料所需的新概念将扩大能量和温度范围，以描述过渡金属材料（例如铜和铁基超导体）中的相关现象。该领域的许多关键问题都涉及具有根本重要性的问题，例如量子临界物理学、各向异性超导机制以及非费米液体行为的起源。受到两种新的、不寻常的重费米子超导体发现的激励，PI 将应用他最近开发的一种新型大 N 展开式来实现重电子超导。对重电子量子临界性的新见解和近藤自旋液体材料的发现激励 PI 开始对近藤晶格的相图进行一系列新的研究。最近发现了多铁氧化物中的磁调谐临界终点。 PI将开展一项新的研究计划，研究多铁材料中的场调谐量子临界性。对“硬凝聚态物理”各个方面的研究对于新物理概念和材料新想法的发展发挥着重要的推动作用未来的。例如，量子临界点使超导性和其他新物质相成核的显着趋势对材料的开发具有很大的意义；另一方面，量子相变的新普适性类别具有重大的根本意义，并且像它们在统计力学中的经典前辈一样，可能会在宇宙学和粒子物理领域得到推广和未来应用。这是学生学习理论物理的先进方法，同时与实验物理和真实材料保持密切联系的绝佳领域。PI 坚定地致力于物理学的多样性，长期以来一直支持物理学界的女性。目前有两名女研究生在他的小组工作。非技术摘要该奖项支持一类称为重电子材料的材料的理论研究和教育。电子在流动量子态和位于稀土或锕系原子周围的量子态中的相互作用导致了一种不寻常的金属态，其特性与教科书一致。这些材料的特性因量子相变的存在而变得更加复杂——相变发生在绝对零温度下，但在一定温度范围内可以感受到强大的影响。 PI 将建立并使用他开发的一种有前途的新方法，以深入了解此类中最近发现的两种材料，即超导体和更广泛的重电子材料。 PI 还将研究这些材料的超导状态。 PI 将进一步探索量子相变在新发现的多铁性材料中发挥的作用，这些材料是未来电子设备中一类很有前途的材料。对超导态和超导性的异常金属态的研究有助于奠定材料研究和超导性的知识基础。这些知识可能导致利用超导体以极低功耗承载电流的能力，以实际的方式实现显着的节能。 PI 坚定地致力于物理学的多样性，长期以来一直支持物理学界的女性。目前有两名女研究生在他的小组工作。