Muon Studies of Quantum Materials and Novel States of Matter

量子材料和新物态的 μ 子研究

• 批准号: RGPIN-2016-04508
• 负责人: Sonier, Jeffrey
• 金额: $ 2.91万
• 依托单位: Simon Fraser University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2020
• 资助国家: 加拿大
• 起止时间: 2020-01-01 至 2021-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=709342
• 关键词: Muon; Studies; Quantum; Materials; Novel

Quantum materials comprise a wide range of scientifically fascinating and technologically important phenomena, including high-temperature superconductivity, non-Fermi liquid behaviour, colossal magnetoresistance, and countless forms of magnetism and ferroelectricity. These unusual behaviours seemingly arise from quantum fluctuations extending beyond a phase transition that has been driven to absolute zero temperature (T = 0) by a non-thermal control parameter (applied pressure, applied magnetic field or chemical manipulation of electron density). Understanding so-called quantum phase transitions (QPTs) and the accompanying emergent quantum phenomena is a grand challenge and a central thrust of modern condensed matter physics. QPTs and associated critical behaviour can be severely modified by disorder. Disorder may be inherent, intentionally introduced by changing the chemical composition, or intrinsically driven by a close competition between different ground states. In general, disorder-induced QPTs are predicted to drive correlated-electron systems to novel quantum disordered phases with rather exotic properties. The investigation of the effects of disorder on quantum critical phenomena necessitates local-probe experimental techniques that are capable of recognizing and characterizing disorder or phase separation in the quantum critical region. The muon spin rotation/relaxation (SR) technique is well suited in this regard to provide insight on QPTs not attainable by other methods. When implanted in a material, the positive muon (+) serves as a local probe of internal magnetic field, allowing measurements of magnetic and superconducting properties. Moreover, SR has a unique sensitivity to volume fractions of magnetic regions. I plan to concentrate my research on SR investigations of quantum materials to provide a local probe's perspective on non-thermal controlled quantum criticality. My approach will be to exploit new SR experimental capabilities in Canada, utilize facilities abroad and forge new research partnerships to gain fundamental insight on quantum critical phenomena in a variety of strongly-correlated electron systems (e.g., topological insulators, unconventional superconductors, novel magnetically-frustrated metals). The proposed research initiatives aim to determine the extent to which phase separation is a ubiquitous phenomenon of magnetic QPTs and to elucidate novel states of matter. The knowledge gained will support quantum materials research and technology, which is a current strategic priority research area in Canada. My research plan provides a fertile HQP training ground for enhancing the workforce skills of trainees through exposure to state-of-the-art technologies, engagement in cutting-edge science, extensive collaborations, and opportunities to travel and disseminate research results.

量子材料构成了广泛的科学迷人和技术上重要的现象，包括高温超导性，非Fermi液体行为，巨大的磁性以及无数形式的磁性和铁电性。这些异常行为似乎是由于量子波动而产生的，该量子波动超出了通过非热控制参数（施加压力，施加的磁场或电子密度的化学操纵）驱动到绝对零温度（t = 0）的延伸。理解所谓的量子相变（QPT）和随附的新兴量子现象是现代冷凝物理物理学的巨大挑战，也是核心。 QPT和相关的临界行为可以通过疾病严重改变。疾病可能是固有的，是通过改变化学成分的意图引入的，或者是由不同基础状态之间的近距离竞争而固有驱动的。通常，预计无序诱导的QPT将驱动相关的电子系统到具有相当异国特性的新型量子无序相。 对疾病对量子关键现象的影响的研究需要局部探针实验技术，这些技术能够识别和表征量子关键区域中的疾病或相位分离。在这方面，MUON自旋旋转/松弛（SR）技术非常适合提供对其他方法无法实现的QPT的见解。当植入材料中时，阳性（+）充当内部磁场的局部探针，从而测量了磁性和超导性能。此外，SR对磁区域的体积分数具有独特的敏感性。 我计划将研究集中在量子材料的SR研究上，以提供当地探测器对非热控制量子关键的看法。我的方法是利用加拿大的新SR实验能力，在国外利用设施并建立新的研究伙伴关系，以获得对各种强相关的电子系统（例如，拓扑绝缘子，不常规的超管制，新颖的磁性磁性金属的新型绝缘体）中对量子关键现象的基本见解。 拟议的研究计划旨在确定相位分离是磁性QPT的普遍现象并阐明物质的新状态的程度。获得的知识将支持量子材料研究和技术，这是加拿大当前的战略优先研究领域。我的研究计划提供了一个肥沃的HQP培训场地，可通过接触最先进的技术，尖端科学，广泛的合作以及旅行和传播研究结果的机会来提高受训者的劳动力技能。