Spin fluctuations in itinerant electron systems

流动电子系统中的自旋涨落

• 批准号: 1506704
• 负责人: Emilia Morosan
• 金额: $ 44.07万
• 依托单位: William Marsh Rice University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-07-15 至 2019-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1506704&HistoricalAwards=false
• 关键词: Spin; fluctuations; itinerant; electron; systems

NON-TECHNICAL ABSTRACT: While a century old problem, magnetism remains poorly understood. Of the two extreme magnetic states - those with magnetic moments localized in small spatial volumes (local moments) and those shared by the entire compound (itinerant moments), the former remains better described theoretically, with most real materials actually residing in the continuum between the two. The main goal of this project is to discover and characterize novel itinerant magnets without magnetic elements. It is of particular interest to understand what happens as the temperature is lowered close to absolute zero, or towards quantum phase transitions (QPT), fundamentally distinct transitions compared to the more familiar phase transitions, for example liquid-to-solid. Exotic physics is believed to emerge from QPTs and these will be studied with tuning parameters such as composition, pressure or magnetic field. Undergraduate and graduate students involved in the project will be trained in crystal growth and characterization, valuable tools for materials driven condensed matter research. The PI will develop a class on scientific presentation skills, and will establish two series of lab open houses, for hands-on experience for children and for adults.TECHNICAL ABSTRACT: This NSF award supports experimental investigations and education in condensed matter physics, with focus on novel magnetic states of matter in the itinerant moment regime. In particular, the goal of this proposal is to investigate novel itinerant magnets containing no magnetic elements, where the the chemical tunability of the only three known such magnetic systems will be explored towards designing the new compounds of interest. The main thrusts of the project are studies of (i) the correlations between the structural and physical properties of itinerant electron magnets, (ii) the interplay between electronic and magnetic ground states and (iii) non-Fermi liquid behavior in itinerant magnet systems. In addition, the recently discovered hardness of some related alloys will be investigated and the materials optimized for medical and possibly new technological applications. The PI will develop a class on scientific presentation skills, and will establish two series of lab open houses, for hands-on experience for children and for adults.

摘要：作为一个有百年历史的问题，人们对磁学仍然知之甚少。在磁矩局限于小空间体积（局部磁矩）和整个化合物共享的磁矩（流动磁矩）这两种极端磁态中，前者在理论上得到了更好的描述，大多数真实材料实际上位于两者之间的连续体中。该项目的主要目标是发现和表征无磁性元件的新型流动磁铁。当温度降低到接近绝对零度或接近量子相变（QPT）时会发生什么，这是特别有趣的，与更熟悉的相变（例如液体到固体）相比，量子相变是根本不同的转变。奇异的物理被认为是从量子点中产生的，这些将通过调整参数（如成分、压力或磁场）来研究。参与该项目的本科生和研究生将接受晶体生长和表征方面的培训，这是材料驱动凝聚态研究的宝贵工具。PI将开设一门关于科学陈述技巧的课程，并将建立两个系列的实验室开放日，为儿童和成人提供实践经验。技术摘要：该NSF奖支持凝聚态物理学的实验研究和教育，重点关注流动矩态下物质的新磁态。特别地，本提案的目标是研究不含磁性元素的新型流动磁铁，其中仅有的三种已知的这种磁性系统的化学可调性将被探索，以设计新的感兴趣的化合物。该项目的主要重点是研究(i)流动磁体的结构和物理性质之间的相关性，（ii）电子基态和磁性基态之间的相互作用，以及（iii）流动磁体系统中的非费米液体行为。此外，还将研究最近发现的一些相关合金的硬度，并优化用于医疗和可能的新技术应用的材料。PI将开设一门关于科学陈述技巧的课程，并将建立两个系列的实验室开放日，为儿童和成人提供实践经验。