Pressure- and Field-Tuned Spectroscopy of Strongly Spin-Lattice-Coupled Materials

强关联材料中原子自旋和晶格之间的强耦合与许多重要的科学和技术上有用的现象有关，包括轨道有序化、多铁性行为以及磁场和压力可调的相变。该个人研究人员奖支持一个项目，该项目将涉及各种单晶氧化钌、氧化镁和氧化钒材料的生长、表征和光学光谱测量，这些材料的性能对外加压力和/或磁场的响应得到了极大的增强(“巨大”)，使这些材料有望成为下一代“功能”材料和器件的候选材料。这个项目的目标是通过使用磁场和压力调谐的光学光谱来研究这些材料的各种低温、强磁场和高压相中自旋-晶格耦合和自旋/晶格动力学演化的方式，以了解这些奇特而有用的性质的微观起源。该项目的预期成果包括：(I)阐明这些材料在高压和外加磁场作用下表现出的巨大敏感性的微观来源；(Ii)洞察如何生长具有增强功能特性的新材料；以及(Iii)将向科学界其他人提供相关材料的高质量单晶样本。该项目还将为2名研究生提供单晶生长和压力和磁场调谐光学光谱学方面的广泛培训，并将作为通过参观高场/高压光学实验室而引起K-12学生对科学感兴趣的外联计划的一部分。在许多基于氧化物的材料中，原子磁矩(可以被认为是附着在原子上的小条形磁铁)和原子的有序“晶格”结构之间存在着特别强的相互作用；这种强烈相互作用的一个重要结果是，可以使用外加压力或磁场来灵敏地控制这些材料中电子的迁移率、磁性，甚至结构形状。因此，这些“高度可调”的材料有望成为下一代多功能开关、传感器、形状记忆结构和其他有用的电子/磁性设备的候选材料。这一个人研究人员奖支持一个项目，该项目将涉及这些基于氧化物的新型材料的生长，以及通过散射材料的光(即“光子”)，同时通过在高压和强磁场中发现的新相调整材料的性能来研究导致其奇异性能的基本机制。该项目的目标是更好地了解导致这些材料“高度可调”特性的条件(I)阐明物质在新的环境条件下的行为，以及(Ii)开发具有增强功能特性的新材料。该项目还将为2名研究生提供材料生长和最先进的光散射方法方面的广泛培训，并将作为通过参观高场/高压光学实验室来吸引K-12学生对科学感兴趣的外联计划的一部分。

TECHNICAL ABSTRACTStrong coupling between atomic spins and the lattice in "strongly correlated" materials is associated with many scientifically important and technologically useful phenomena, including orbital ordering, multiferroic behavior, and magnetic-field- and pressure-tunable phase transitions. This individual investigator award supports a project that will involve the growth, characterization, and optical spectroscopic measurement of various single-crystal ruthenium-oxide, magnesium-oxide, and vanadium-oxide materials whose properties have highly enhanced ("colossal") responses to applied pressure and/or magnetic field, making these materials promising candidates for the next generation of "functional" materials and devices. The goal of this project is to understand the microscopic origin of these exotic and useful properties, by employing magnetic-field- and pressure-tuned optical spectroscopy to investigate the manner in which spin-lattice coupling and spin/lattice dynamics evolve through various low temperature, high-magnetic-field, and high pressure phases of these materials. Among the anticipated outcomes of this project are (i) elucidation of the microscopic origin of the colossal sensitivities these materials exhibit in response to high pressures and applied magnetic fields; (ii) insights into how to grow new materials with enhanced functional properties; and (iii) high quality single-crystal samples of correlated materials that will be made available to others in the scientific community. This project will also provide broad training to 2 graduate students in single-crystal growth and pressure- and magnetic-field-tuned optical spectroscopy, and will be used as part of an outreach program to interest K-12 students in the sciences via tours of the high field/high pressure optical laboratory. NON-TECHNICAL ABSTRACTIn many oxide-based materials, there is a particularly strong interaction between the atomic magnetic moments (which can be thought of as small bar magnets attached to the atoms) and the ordered "lattice" structure of the atoms; one important consequence of this strong interaction is that applied pressures or magnetic fields can be used to sensitively control the mobility of the electrons in, the magnetic properties of, and even the structural shape of, these materials. As a consequence, these "highly tunable" materials are promising candidates for the next generation of multi-functional switches, sensors, shape-memory structures, and other useful electronic/magnetic devices. This individual investigator award supports a project that will involve the growth of these novel oxide-based materials, and the study of the basic mechanisms responsible for their exotic properties by scattering light (i.e., "photons") from the materials while tuning the materials' properties through their novel phases found at high pressures and high magnetic fields. The goals of this project are to better understand the conditions responsible for the "highly tunable" properties of these materials (i) to elucidate how matter behaves under novel environmental conditions, and (ii) to develop new materials with enhanced functional properties. This project will also provide broad training to 2 graduate students in materials growth and state-of-the-art light scattering methods, and will be used as part of an outreach program to interest K-12 students in the sciences via tours of the high field/high pressure optical laboratory.