Detecting fractionalization in strongly correlated magnets

检测强相关磁体中的分数化

• 批准号: EP/V038281/1
• 负责人: Ioannis Rousochatzakis
• 金额: $ 35.75万
• 依托单位: Loughborough University
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2021
• 资助国家: 英国
• 起止时间: 2021 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=EP%2FV038281%2F1
• 关键词: Detecting; fractionalization; strongly; correlated; magnets

Understanding the properties of materials from microscopic principles has been one of the major triumphs of Science, and one that has underpinned the development of modern technologies, from the innovation of computers and magnetic storage devices to fibre-optic communications, lasers and mag- netic resonance imaging. Much of this progress has been made possible by harnessing the quantum properties of matter at the atomic level, an achievement that can hardly be overstated, given that the effects of quantum mechanics cannot be directly perceived by the naked eye.An exciting frontier of current research, and one that holds the promise for the next generation of quantum technologies, concerns materials with so-called topological order, where quantum mechanical effects can survive and become manifest at macroscopic length scales. Quantum spin liquids are prime exponents for such orders. In conventional magnets, the underlying spins of the atoms order at low temperatures in a characteristic pattern that minimizes their interaction energy. Under certain conditions, however, the interactions cannot fix the relative orientations of the spins uniquely, due to the presence of an infinite number of competing low-energy configurations. As a result the spins evade ordering and continue to fluctuate down to zero temperature. Quantum spin liquids arise as macroscopic coherent superpositions of such low-energy configurations when the quantum mechanical tunnelling between these configurations is pronounced enough. Such a macroscopic coherence can endow the system with a number of remarkable collective properties, such as the fractionalization of spins into fermions and gauge fields (emergent degrees of freedom similar to the electromagnetic fields of light), and topologically protected ground states that can act as fault-tolerant qubits.After decades of theoretical and experimental work on candidate materials, some of which have been discovered only in the last 10-15 years, we now have a good understanding of the underlying conditions that favour the formation of quantum spin liquids. One of the major remaining challenges, and the one addressed in this proposal, is to develop quantitative diagnostic tools for the unambiguous detection of spin liquids and fractionalization in rear materials. The numerical and semi-analytical many-body platforms proposed here aim at the heart of this challenge and the so-called magnon- spinon dichotomy observed time and again in numerous strongly correlated magnets in dynamical scattering experiments. The results will help to establish the distinctive fingerprints of fractionalization in realistic non-integrable models and unravel the microscopic organising principles of candidate materials that are currently actively pursued.

从微观原理理解材料的性质一直是科学的主要成就之一，也是现代技术发展的基础，从计算机和磁存储设备的创新到光纤通信、激光和磁共振成像。这些进展中的很大一部分都是通过利用原子水平上物质的量子特性而实现的，考虑到量子力学的效应无法用肉眼直接感知，这一成就怎么说都不为过。当前研究的一个令人兴奋的前沿领域，也是下一代量子技术的希望所在，涉及具有所谓拓扑有序的材料，量子力学效应可以在宏观长度尺度上存在并变得明显。量子自旋液体是这种阶数的素指数。在传统磁体中，原子的基本自旋在低温下以一种特征模式排列，使它们的相互作用能最小化。然而，在某些条件下，相互作用不能唯一地固定自旋的相对取向，因为存在无限数量的竞争低能组态。结果，自旋逃避了有序，继续波动到零温度。当这些低能量组态之间的量子力学隧穿足够明显时，量子自旋液体作为这些组态的宏观相干叠加而出现。这种宏观相干性可以赋予系统许多显著的集体性质，例如自旋分裂成费米子和规范场（类似于光的电磁场的涌现自由度），以及可以充当容错量子比特的拓扑保护基态，经过数十年对候选材料的理论和实验工作其中一些是在最近10-15年才发现的，我们现在对有利于量子自旋液体形成的基本条件有了很好的了解。剩余的主要挑战之一，在本提案中解决的一个，是开发定量诊断工具，明确检测自旋液体和分馏后材料。这里提出的数值和半解析多体平台的目标是这个挑战的核心和所谓的磁振子-自旋二分法观察到的时间和时间，并再次在许多强相关的磁铁在动态散射实验。这些结果将有助于在现实的不可积模型中建立独特的分馏指纹，并揭示目前正在积极追求的候选材料的微观组织原理。

项目成果

Magnetic excitations and interactions in the Kitaev hyperhoneycomb iridate ß - Li 2 IrO 3

Kitaev 超蜂窝铱酸盐中的磁激发和相互作用 - Li 2 IrO 3

• DOI: 10.1103/physrevb.106.064423
• 发表时间: 2022
• 期刊: Physical Review B
• 影响因子: 3.7
• 作者: Halloran T

Multi- Q magnetic phases from frustration and chiral interactions

来自挫败和手性相互作用的多 Q 磁相

• DOI: 10.1103/physrevb.108.024412
• 发表时间: 2023
• 期刊: Physical Review B
• 影响因子: 3.7
• 作者: Georgiou M

Signatures of non-Loudon-Fleury Raman scattering in the Kitaev magnet β−Li2IrO3

Kitaev 磁体 βLi2IrO3 中非劳登-弗勒里拉曼散射的特征

• DOI: 10.1103/physrevb.105.l241101
• 发表时间: 2022
• 期刊: Physical Review B
• 影响因子: 3.7
• 作者: Yang, Yang;Wang, Yiping;Rousochatzakis, Ioannis;Ruiz, Alejandro;Analytis, James G.;Burch, Kenneth S.;Perkins, Natalia B.
• 通讯作者: Perkins, Natalia B.