Investigation of Quantum Matter by Quantum Point Magnetic Probes

量子物质是一种电子的量子力学性质在新的性质中明确表现出来的材料。它的范围从实现称为自旋液体的特殊基态的自旋受阻磁系统，到宏观电流无阻力流动的超导。我最近的研究过程不仅是寻找可能实现量子力学基态的实际材料，而且还通过磁场等外部条件来控制它们，实现物质的新相。我的另一个研究过程是找到电子的多个自由度之间的相互作用：自旋、电荷和电子所在轨道的形状。这项研究集中在量子物质的五个主题：(1)受阻自旋系统的基态性质和磁场中新相的起源，特别是在(A)有/没有自旋-轨道耦合的几何受阻自旋系统和(B)金属手性磁体；(2)受阻磁体中的猝灭无序效应和动态自旋关联；(3)超导系统中的竞争基态及其控制；以及(4)用量子力学杂质表征基于半导体的量子物质。这些研究课题旨在发现一类新的材料，实现由外部条件产生的量子态和/或新相。这一结果可能解释电子的量子态与环境参数之间的关系。研究方法包括寻找可能实现量子物质状态的新材料，并用加拿大TRIUMF加速器研究所提供的最灵敏的磁性探测器：µ子和锂-8核来表征这些材料。这些材料的静态和动态特性可以用这种探测方法来研究，并将与现有的理论进行比较。结果将为理论框架和/或材料合成提供反馈。6名本科生和5名博士生将接受培训，以获得材料合成经验、基本表征技术、使测量成为可能的硬件设计，以及在计算机中模拟材料的数据分析和理论计算。其成果的出版将培训高素质人员(HQP)的陈述和沟通技能，既面向普通公众，也面向其研究领域的专家。这些技能将使HQP在学术界和工业界的职业生涯中具有竞争力。这项研究将使加拿大受益，因为它开创了量子物质研究的先河，并确定了新的相，这可能会导致未来的应用。

Quantum Matter is the kind of material where the quantum mechanical nature of electrons manifests itself explicitly in novel properties. It ranges from a spin frustrated magnetic system which realizes a peculiar ground state called spin liquid, to superconductivity where macroscopic electrical currents flow without resistance. The recent course of my research is not only to find the actual materials which may realize quantum mechanical ground states, but also to control them by external conditions, such as magnetic fields, to realize a new phase of matter. Another course of my research is to find the mutual interactions between the multiple degrees of freedom of electrons: spin, charge and the shape of the orbital where the electron resides. This research proposal focuses on five topics in quantum matter: (1) ground state properties of frustrated spin systems and the origin of new phases in magnetic fields, particularly in (a) geometrically frustrated spin system with/without spin-orbit couplings and (b) metallic chiral magnets; (2) effect of quenched disorder in frustrated magnets and dynamical spin correlations; (3) competing ground states and their control in superconducting systems; and (4) characterization of semiconductor-based quantum matter by quantum mechanical impurities. These research topics aim to discover a new class of materials which realizes the quantum states and/or new phases created by the external conditions. The result may elucidate the relation between the quantum states of electrons and the environmental parameters. The research method involves searching for new materials which may realize the quantum matter state, and characterizing those materials with the most sensitive magnetic probes: muons and lithium-8 nuclei, which are available at TRIUMF, Canada's accelerator research institute. The static and dynamical features of these materials may be investigated by this probe method and will be compared with the existing theories. The results will give feedback to the theoretical framework and/or the materials synthesis. Six undergraduate students and five PhD students will be trained to gain materials synthesis experience, basic characterization techniques, design of the hardware to make the measurements possible, in addition to the data analysis and theoretical calculations which simulate the materials in the computer. The publication of their results will train the presentation and communication skills of the highly qualified personnel (HQP), both to the general public and to the specialists in their research field. These skills will enable HQPs to be competitive for careers in academia and industry. This research will benefit Canada by pioneering quantum matter research and identification of new phases, which may lead to future applications.