Ground States of Disordered Quantum Magnets

无序量子磁体的基态

• 批准号: 1205165
• 负责人: Ian Fisher
• 金额: $ 36.5万
• 依托单位: Stanford University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-09-01 至 2016-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1205165&HistoricalAwards=false
• 关键词: Ground; States; Disordered; Quantum; Magnets

****Technical Abstract****The aim of the proposed research is to obtain a deeper understanding of the multifaceted roles that disorder can play in complex materials. Arguably the most exciting and challenging regimes are the ones in which quantum fluctuations play a significant role. Disordered spin dimer compounds fall in to this general class of material, providing, at least in principle, well-controlled access to specific problems of interest, including Bose glass behavior, random singlet formation, and ordered states that arise as a consequence of quenched disorder. The proposed research will focus on the effects of disorder in this class of material, about which relatively little is known, and from which one can hope to glean important insights relevant to the broader class of quantum materials. Various chemical substitutions can be used to create different types and strengths of disorder in a variety of archetypal compounds, the effects of which will be studied via measurements of the low temperature thermodynamic properties as a function of the chemical composition. Single crystals of the materials studied will be grown in the PIs laboratory. The award will support the education and activities of a graduate student in these areas. ****Non-Technical Abstract****Disorder of one form or another is remarkably common in many advanced materials of technological importance, including high-temperature superconductors and materials exhibiting colossal magnetoresistance. Whether the disorder is an irrelevant distraction, that simply accompanies, for example, charge doping, or whether it plays a more central role in determining the associated phase diagrams of these materials is a matter of ongoing research and debate. Given the prevalence of disorder in these complex and incompletely understood materials, it is important to understand its effects in simpler and better controlled model systems. It is the purpose of this program to study disordered magnets in regimes which have not previously been extensively explored, with the broad aim of developing a deeper understanding of the effects of disorder in the broad class of quantum materials. The project involves both low temperature measurements, and also an extensive crystal growth effort. This crystal growth program has a broader impact by serving the larger condensed matter community via external collaborations, ensuring the wide availability of contemporary materials for the US condensed matter community, and addressing the perceived need for increased emphasis on materials synthesis within the US. The award will support the education of a graduate student in these technologically important areas.

* 技术摘要 * 拟议研究的目的是更深入地了解无序在复杂材料中可能发挥的多方面作用。可以说，最令人兴奋和最具挑战性的制度是量子涨落发挥重要作用的制度。无序的自旋二聚体化合物属于这类材料，至少在原则上，提供了对感兴趣的特定问题的良好控制的访问，包括玻色玻璃行为，随机单态形成，以及由于淬灭无序而产生的有序状态。拟议的研究将集中在这类材料中无序的影响上，对此知之甚少，人们希望从中收集与更广泛的量子材料相关的重要见解。各种化学取代可用于在各种原型化合物中产生不同类型和强度的无序，其效果将通过测量作为化学组成的函数的低温热力学性质来研究。所研究材料的单晶将在PI实验室中生长。该奖项将支持这些领域的研究生的教育和活动。* 非技术摘要 * 一种或另一种形式的无序在许多具有技术重要性的先进材料中非常常见，包括高温超导体和表现出巨大磁阻的材料。这种紊乱是否是一种无关紧要的干扰，仅仅伴随着例如电荷掺杂，或者它是否在确定这些材料的相关相图中起着更重要的作用，这是一个正在进行的研究和辩论的问题。考虑到这些复杂和不完全理解的材料中疾病的流行，重要的是要在更简单和更好的控制模型系统中了解其影响。该计划的目的是研究以前未被广泛探索的制度中的无序磁体，其广泛目的是更深入地了解量子材料中的无序效应。该项目既涉及低温测量，也涉及广泛的晶体生长工作。该晶体生长计划通过外部合作为更大的凝聚态社区提供服务，确保美国凝聚态社区广泛获得当代材料，并解决美国国内对材料合成日益重视的需求，从而产生更广泛的影响。该奖项将支持这些技术重要领域的研究生教育。