Collaborative Research: Frustration, glassiness and spin liquids: from dirty to pristine materials

合作研究：挫败感、玻璃质和旋转液体：从脏材料到原始材料

基本信息

批准号：
2218130
负责人：
Arthur Ramirez
金额：
$ 53.36万
依托单位：
University of California-Santa Cruz
依托单位国家：
美国
项目类别：
Continuing Grant
财政年份：
2022
资助国家：
美国
起止时间：
2022-09-01 至 2026-08-31
项目状态：
未结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=2218130&HistoricalAwards=false
关键词：
Collaborative Research Frustration glassiness spin

项目摘要

Non-technical abstractCurrently, immense global experimental efforts are directed at finding quantum spin liquids (QSLs), a theoretically-predicted state of magnetic materials in which the spins, or atom-size bar-magnets, exhibit liquid-like properties down to the lowest possible temperatures. QSLs can be efficiently used to create quantum bits, “qubits”, as they can store information encoded simultaneously in the states of multiple spins, and hence protected from local noise. Thus, QSLs hold great promise as a platform for future computing and communication technology. A present barrier to their realization is randomly located impurities and defects that can convert a QSL into another state of matter, “spin glass”, in which the spins freeze in random orientations, similar to how silicon atoms possess random positions in window glass. This research investigates the effect of impurities and defects on the fundamental properties of geometrically frustrated magnets, the largest class of materials in which QSLs are being sought. Through systematically controlling defects during material synthesis, and theoretically modeling the resulting behavior, the team is laying the foundations for future engineering of QSL-based devices. The broader impacts of this research are both the development of synthesis methods for reducing defects in crystalline specimens and the theoretical understanding that will inform future processing endeavors. In addition, the research helps train junior researchers directly involved in the project, as well as the broader community through instructional media and data that are accessible on open-source platforms such as the NSF’s Crystal Sample Archive. Technical abstractThis research is a combined experimental and theoretical effort to systematically investigate the effect of quenched disorder on collective magnetism in geometrically frustrated (GF) materials and to determine the synthesis barriers to obtaining pure materials. The research includes synthesis of materials spanning the entire range of spin density from dilute spin, to concentrated disordered spins, to dilute impurities, en route to ultra-pure materials. Part of the work uses quenched disorder as a probe of fundamental properties of GF magnetism. The measurements of the thermodynamic properties of disordered GF materials aim to uncover microscopic Hamiltonians of GF systems, reveal possible universality classes of disorder-induced spin-glass transitions, investigate the origin of the recently discovered “hidden energy scale” in these systems and reveal the nature of elementary excitations in them. The work includes theoretical calculations of the thermodynamic manifestations of the microscopic details of the Hamiltonians, exploring the interplay of different types of disorder in GF media and constructing models for the “hidden energy scale” and the behavior of heat capacity in GF magnets, which is used to make prediction and explain experimental data. Part of this research may result in obtaining materials that exhibit strong quantum-spin-liquid behavior and demonstrating the irrelevance of quenched disorder in them.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

非技术抽象的目前，巨大的全球实验努力旨在寻找量子自旋液体（QSLS），这是一种理论预测的磁性材料状态，其中自旋或原子大小的条形棒状体，暴露于液体样特性，以至于可能最低的温度。 QSL可以有效地用于创建量子位，即“ Qubits”，因为它们可以简单地存储在多个旋转状态中编码的信息，因此可以保护局部噪声。这是QSL作为未来计算和通信技术平台的巨大希望。他们实现的当前障碍是随机位置的杂质和缺陷，可以将QSL转换为另一个物质状态，即“自旋玻璃”，其中旋转以随机取向冻结，类似于硅原子在窗玻璃中具有随机位置的方式。这项研究调查了杂质和缺陷对几何沮丧磁铁的基本特性的影响，这是QSL被伤痕累累的最大材料类别。通过在材料合成过程中系统地控制缺陷，以及对所得行为进行理论建模，团队正在为基于QSL的设备的未来工程奠定基础。这项研究的更广泛的影响既是用于减少晶体标本缺陷的合成方法的开发，又是理论理解，这将为未来的处理努力提供依据。此外，该研究还可以通过在NSF的Crystal Sample Archive等开源平台上访问的教学媒体和数据来帮助培训直接参与该项目的初级研究人员以及更广泛的社区。技术摘要这项研究是一项合并的实验和理论上的努力，可以系统地研究淬火障碍对几何沮丧（GF）材料中集体磁性的影响，并确定获得纯材料的合成障碍。该研究包括合成从稀释型自旋到浓缩物无序旋转到稀释杂质的整个自旋密度范围的材料的合成，并在超出质材料的途中。一部分工作使用淬火障碍作为GF磁性基本特性的探测。无序GF材料的热力学特性的测量旨在揭示GF系统的微观哈密致力体，揭示了疾病诱导的旋转玻璃转变的普遍性类别，研究了这些系统中最近发现的“隐藏能量量表”的起源，并揭示了其中基本激励的性质。这项工作包括对哈密顿人微观细节的热力学表现的理论计算，探索了GF媒体中不同类型疾病的相互作用，并为“隐藏能量量表”的模型以及GF磁体中的热容量的行为构建模型，该模型用于进行预测和解释实验数据。这项研究的一部分可能导致获得表现出强大的量子自旋液体行为的材料，并证明了淬火障碍无关紧要。该奖项反映了NSF的法定任务，并被认为是通过基金会的智力优点评估和更广泛影响的审查标准来通过评估来获得的支持。