Electrodynamics of topological and quantum materials

拓扑和量子材料的电动力学

• 批准号: RGPIN-2018-06737
• 负责人: Dodge, JSteven
• 金额: $ 3.64万
• 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: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=762445
• 关键词: Electrodynamics; topological; quantum; materials

Soon after quantum mechanics was invented, physicists like Einstein began to apply it to understand the properties of solids. Normally we associate quantum mechanics with small things, like atoms or subatomic particles. But the quantum theory of solids is one of the great intellectual achievements of the twentieth century, and has transformed society by enabling the invention of the transistor, the semiconductor laser, and high-density magnetic storage. Yet for all our know-how, physicists who study these things still encounter a variety of phenomena that present fundamental challenges to the theories found in textbooks. In some materials, electrons can be prevented from conducting electricity by their mutual repulsion, which causes them to get stuck, like cars in a quantum parking lot; in others, the electrons spontaneously self-organize in arrangements that cause the symmetry of the whole material to change; still others are electrical insulators that are encased by a thin metallic sheet at the surface, which have been dubbed “topological insulators” for reasons that take more than this space allows. All of them represent frontiers of our current understanding, and to emphasize this unity, Canadian researchers coined the term quantum materials to describe them. Research on quantum materials is now a dominant theme in contemporary research on solids. Like earlier research on the solid state, it promises to both advance our understanding of matter and expand our capacity to engineer new electronic materials, laying the foundation for future technology as it deepens our appreciation of nature. One of the most basic questions we can ask about a solid is how it responds to light, so optics plays an important role in this research. We can see the difference between an electrical insulator, such as glass, and a metal, such as aluminum, just by looking at them. By extending this to wavelengths beyond the visible, our research in experimental optical spectroscopy allows us to see more about the solid than we could with our eyes. The goal of my research program is to exploit modern lasers in research on quantum materials research. We can use pulsed lasers at visible wavelengths to generate far-infrared light, known as terahertz waves, which we can use to readily tell the difference between a superconductor and a metal. With intense polarized light from a laser we can identify many of the fundamental symmetries of solids with exquisite sensitivity, which further allows us to detect how these symmetries change if the electrons spontaneously self-organize. And with intense bursts of light we can also change solids and watch them evolve, exciting them out of equilibrium and then characterizing how they return to their original state, or pushing them into an altogether different one. Through these techniques, we aim to understand quantum materials more deeply, so that someday we might put them to use as we have with silicon.

量子力学发明后不久，像爱因斯坦这样的物理学家就开始应用它来理解固体的性质。通常我们将量子力学与原子或亚原子粒子等小事物联系起来，但固体的量子理论是人类伟大的智力成就之一。二十世纪，并通过晶体管、半导体激光器和高密度磁存储的发明改变了社会。然而，尽管我们拥有所有的专业知识，研究这些东西的物理学家仍然遇到了各种带来根本性挑战的现象。到理论在一些材料中，电子可以通过相互排斥来阻止导电，这会导致它们被卡住，就像量子停车场中的汽车一样，在另一些材料中，电子会自发地自我组织，从而导致对称性。整个材料的变化；还有一些是表面被薄金属片包裹的电绝缘体，它们被称为“拓扑绝缘体”，因为其占用的空间超出了我们所允许的范围。为了强调这种统一性，加拿大研究人员创造了“量子材料”一词来描述它们，就像早期的固体研究一样，它有望促进我们的理解。我们可以提出的关于固体的最基本问题之一是它如何响应光，因此光学发挥着重要作用。我们可以在这项研究中看到电气之间的区别。绝缘体（例如玻璃）和金属（例如铝），只需观察它们即可将其扩展到可见光之外的波长，我们对实验光谱学的研究使我们能够比肉眼看到更多关于固体的信息。我的研究计划的目标是在量子材料研究中利用现代激光器，我们可以使用可见波长的脉冲激光来产生远红外光，即太赫兹波，我们可以用它来轻松区分超导体。利用激光发出的强偏振光，我们可以以极高的灵敏度识别固体的许多基本对称性，这进一步使我们能够检测到如果电子自发自组织，这些对称性如何变化。还可以改变固体并观察它们的演化，激发它们脱离平衡，然后描述它们如何返回到原始状态，或者将它们推向完全不同的状态，通过这些技术，我们的目标是更深入地了解量子材料，以便有一天。我们可能会把它们放在像我们使用硅一样使用。