Strongly Correlated Electron Behavior in Intermetallics with an Emphasis on Novel Borides, Carbides, and Noncentrosymmetric Systems

*非技术摘要*这一个人研究人员奖支持专注于合成具有非常独特的物理性质的材料的研究，这些材料是由于材料中电子之间的强烈关联而产生的。这些性质之一是超导电性。当一种材料变成超导体时，它就失去了对电流的所有阻力。材料中的电子如何真正完成这一惊人的壮举一直是许多实验和理论研究的目标。现在已经知道，超导态取决于许多因素，其中之一是材料的结构。该项目的一个目标是阐明超导电性如何与新材料的结构有关，其中许多材料含有碳或硼。这些元素通常在它们的化合物中形成大的结构单元。这种增加的结构复杂性允许在超导性能方面进行更大范围的优化。该项目的另一个目标是研究新材料的改进和发现，这些新材料可用于新兴的自旋电子学(基于自旋的电子学)领域，该领域不仅利用电子上的电荷，而且利用其固有的磁性，即自旋和磁矩。为自旋电子学应用找到更好的材料可能会给计算机内存行业带来革命性的变化。本奖项所提供的实验研究结果将与相关理论进行比较，有助于我们对强关联电子系统的总体理解。这项研究可能会导致发现具有奇异磁性或电学性质的新材料。这项研究将被整合到一个教育计划中，该计划将在三年内加强研究生和本科生在实验室和课堂上的学习。这项实验研究将为博士后助理、研究生和本科生提供在材料合成、结构表征、物理性质随温度和磁场的函数测量以及数据采集和分析方面的宝贵经验。*技术摘要*这一个人研究人员奖支持对新型金属间化合物系统中的电子和磁基态的实验研究。该项目的重点将是金属间化合物、碳化物和非中心对称系统。这些强相关的电子材料敏感地依赖于诸如样品化学计量比、载流子密度、温度、化学/物理压力和磁场等参数。金属间化合物系统表现出从超导体到近藤绝缘体到高温铁磁性的广泛的基态。合成和研究具有非传统配对对称性的新型非中心对称超导体，如Mo(3)Al(2)C，将使理论工作与实验结果相比较。将近藤绝缘体(如FeSi)化学掺杂到高温铁磁体中，并控制碱土六硼化物的高温铁磁性，可能会在新兴的自旋电子学领域产生重要的技术应用。这一奖项带来的实验结果将有助于我们对强关联电子系统的总体理解。这项研究可能会导致发现具有奇异磁性或电学性质的新材料。这项研究将被整合到一个教育计划中，该计划将在三年内加强研究生和本科生在实验室和课堂上的学习。这个实验项目将为博士后助理、研究生和本科生提供在材料合成、结构表征、作为温度和磁场函数的物理性质的测量以及数据采集和分析方面的宝贵经验。

****NON-TECHNICAL ABSTRACT****This individual investigator award supports research focusing on the synthesis of materials that possess very unique physical properties resulting from strong correlations between the electrons in the material. One of these properties is superconductivity. When a material becomes a superconductor, it loses all of its resistance to the flow of electricity. How the electrons in a material actually accomplish this amazing feat has been the goal of much experimental and theoretical research. It is now known that the superconducting state depends on many factors, one of which is the material's structure. One goal of this project is to elucidate how superconductivity is related to the structure of novel materials, many of which contain carbon or boron. These elements often form large structural units in their compounds. This increased structural complexity allows a greater range of optimization in the superconducting properties. Another goal of the project is to investigate the improvement and discovery of new materials that can be utilized for applications in the emerging field of spintronics (spin-based electronics), which exploits not only the charge on the electron, but also its intrinsic magnetic properties; "spin" and "magnetic moment." Finding a better material for spintronics applications could revolutionize the computer memory industry. The results obtained from the experimental studies enabled by this award will be compared to the relevant theories and will aid in our understanding of strongly correlated electron systems in general. This research could lead to the discovery of new materials that display exotic magnetic or electronic properties. The research will be integrated into an educational plan, which over a 3-year period is intended to enhance both graduate and undergraduate learning in the laboratory and classroom. This experimental research will provide post-doctoral associates, graduate, and undergraduate students with valuable experience in the areas of materials synthesis, structural characterization, measurement of physical properties as a function of temperature and magnetic field, and data acquisition and analysis. ****TECHNICAL ABSTRACT****This individual investigator award supports an experimental investigation of the electronic and magnetic ground states in novel intermetallic systems. The focus of the project will be on intermetallic borides, carbides, and noncentrosymmetric systems. These strongly correlated electron materials depend sensitively on parameters such as sample stoichiometry, carrier density, temperature, chemical/physical pressure, and magnetic field. Intermetallic systems exhibit a wide range of ground states ranging from superconductors to Kondo insulators to high temperature ferromagnetism. Synthesizing and investigating new noncentrosymmetric superconductors, such as Mo(3)Al(2)C, with unconventional pairing symmetries will enable theoretical work to be compared to experimental results. Chemical doping of Kondo insulators, for example FeSi, into higher-temperature ferromagnets and control over the high-temperature ferromagnetism in the alkaline earth hexaborides could lead to important technological applications in the emerging field of spintronics. The experimental results enabled by this award will aid in our understanding of strongly correlated electron systems in general. This research could lead to the discovery of new materials that display exotic magnetic or electronic properties. The research will be integrated into an educational plan that over a 3-year period is intended to enhance both graduate and undergraduate learning in the laboratory and classroom. This experimental project will provide post-doctoral associates, graduate, and undergraduate students with valuable experience in the areas of materials synthesis, structural characterization, measurement of physical properties as a function of temperature and magnetic field, and data acquisition and analysis.