Understanding Correlated Electron Ground States: The Magnetic/Superconducting Boundary in Heavy Fermions

该项目研究了一组等电子、等结构的致密近藤化合物，这些化合物显示了高度关联的电子系统的广泛基态：磁性、超导和重费米子，没有其他顺序。利用温度、压力和外加磁场的变量来研究稠密体系和稀薄体系，可以用单离子Kondo标度在低温下演化出的晶格Kondo标度来表征致密Kondo材料。这一特征提供了相关电子系统的分类，这可以首次提供一个框架，用于理解在相关电子系统中发现的基态的强烈变化，这些系统在物理上与技术上感兴趣的不太简单的过渡元素化合物密切相关。这项研究的一个现实目标是首次准确地描述什么是重费米子，并展示它是如何传递到d波段元素的。高中生、本科生和研究生将接受培训，将材料的宽广相空间作为材料驱动凝聚态研究的有效和强大的变量。处于磁性和非磁性之间的金属材料会产生不寻常的电子性能，通常在低温下，并可以显示出一种令人惊讶的超导类型，似乎与高温超导有关。这项研究项目试图通过使用高压和强磁场来研究一组密切相关的化合物来回答这一问题，这些化合物包含稀土元素Ce3+和其他金属，它们在低温下显示出各种有趣的性质。这些结果有望首次为这些材料的物理学带来干净的秩序，这可以为更复杂的具有重要技术意义的过渡元素化合物的物理学提供新的见解，并提出新的研究方向。从高中到研究生水平的学生将通过新材料单晶的生长培训向他们介绍凝聚态物理，为真正理解固体的工作原理提供有价值的基础。

This project studies an isoelectronic, isostructural set of dense Kondo compounds which display a broad spectrum of ground states of highly correlated electron systems: magnetism, superconductivity and heavy Fermion without other order. Using the variables of temperature, pressure and applied external magnetic field to study both the dense and diluted systems, it is possible to characterize dense Kondo materials in terms of a lattice Kondo scale which evolves at low temperature from the single ion Kondo scale. This characterization provides a classification of correlated electron systems which can provide for the first time a framework for understanding the strong variation of ground states found in correlated electron systems, systems which are closely related in their physics to the less simple transition elements compounds of technological interest. A realistic goal of this study is to give for the first time a precise description of what a "heavy Fermion" is and show how this carries over to d-band elements. High school students, college undergraduates and graduate students will be trained to use the broad phase space of materials as an effective and powerful variable in materials driven condensed matter research.%%%%Metallic materials on the border between magnetism and non-magnetism develop unusual electronic properties, usually at low temperature, and can display a surprising type of superconductivity that appears related to high temperature superconductivity. This research project attempts to answer how this comes about through a study using high pressure and high magnetic field to investigate a closely related set of compounds containing the rare earth element Cerium along with other metals, which display a broad variety of interesting properties at low temperature. The results hold the promise to bring for the first time a clean order to the physics of these materials which can provide new insights and suggest new research directions in the more complicated physics of technologically important transition element compounds. Student from high school to graduate level will be introduced to condensed matter physics through training in the growth of single crystals of new materials, providing a valuable underpinning for really understanding how solids work.