Optical studies of quantum materials

该研究计划的目标是双重的：在新材料系统中发现新的物理学，并探索这些材料的潜在应用，这些材料可以提供比现有技术更好的性能。我的团队将建立和开发先进的光学技术，以探测并最终控制新材料中的量子自由度。前两个目标系统是二维（2D）原子薄过渡金属二硫属化物（TMD）和拓扑Weyl半金属（WSM）。这些新兴的材料家族目前引起了极大的兴趣，因为它们为探索新物理提供了新的游乐场。最近发现的单层TMD（例如MoS 2和WSe 2）类似于石墨烯，因为它们是具有六边形蜂窝结构的2D材料。然而，与石墨烯不同，TMD具有半导体带隙。TMD的一个重要特征是，除了自旋自由度之外，电子还具有额外的二元量子自由度，称为谷磁矩。与自旋类似，谷自由度也可以由光控制。这种显着的属性使这些二维半导体的理想平台，以实现新的轻物质耦合，涉及耦合自旋和谷自由度和潜在的自旋和谷为基础的电子和信息处理应用。在我的研究计划中，第一步是使用最先进的光学技术测量这些令人兴奋的TMD中的耦合自旋谷动力学和输运性质。WSM是一类新型的拓扑非平凡量子材料。WSM中的低能激发行为类似于粒子物理中的Weyl费米子。外尔费米子（Weyl fermion）是一种无质量的费米子，具有一定的手征性，是费米子的最基本形式。我的小组将探索光学外尔费米子的动力学，并解决这些基本费米子如何与光子相互作用的问题。WSM还具有吸引人的电学和光学特性，可能会进入未来的电子和光子器件。该研究计划将加深我们对这些奇异材料的基本物理学的理解，并为我们提供自旋，谷和Weyl费米子的弛豫机制和传输特性以及光-物质相互作用强度的精确知识。除了直接的科学影响外，这些研究还将为清洁能源、电子设备和量子信息等几个重要应用带来希望，并将随着这些技术的成熟而提供经济机会。我们打算我们的研究将刺激加拿大工业合作伙伴在下一代智能设备中使用我们的一些研究成果。通过提高能源效率和改进计算能力，公众将从这些先进设备中受益。

The goals of this research program are twofold: to discover new physics in novel materials systems, and to explore potential applications of these materials that offer performance enhancements over existing technology. My group will build and develop advanced optical techniques to probe, and ultimately control, quantum degrees of freedom in new materials. The first two target systems are two-dimensional (2D) atomically-thin transition-metal dichalcogenides (TMDs) and topological Weyl semimetals (WSMs). These emerging materials families are currently of great interest, because they provide new playgrounds to explore new physics.******The recently discovered monolayer TMDs (e.g. MoS2, and WSe2) are analogous to graphene in that they are 2D materials with a hexagonal honeycomb structure. Unlike graphene, however, TMDs possess a semiconductor bandgap. An important feature of TMDs is that, in addition to the spin degree of freedom, an electron has an extra binary quantum degree of freedom, known as valley magnetic moment. Similar to spin, the valley degree of freedom can also be controlled by light. This remarkable property makes these 2D semiconductors an ideal platform to realize novel light-matter coupling involving the coupled spin and valley degrees of freedom and potential spin- and valley-based electronics and information processing applications. The very first step in my research program is to measure the coupled spin-valley dynamics and transport properties in these exciting TMDs using state-of-the-art optical techniques.******WSMs are a novel class of topologically nontrivial quantum materials. The low energy excitations in WSMs behave analogously to Weyl fermions in particle physics. A Weyl fermion is a massless fermion that carries a definite chirality, and is the most basic form of fermion. My group will probe the dynamics of Weyl fermions optically and address the question of how these basic fermions interact with photons. WSMs also possess appealing electrical and optical properties that may make their way into future electronic and photonic devices.******The research program will deepen our understanding of the basic physics in these exotic materials and provide us with a precise knowledge of the relaxation mechanisms and transport properties of spins, valleys and Weyl fermions, as well as the light-matter interaction strengths. Beyond direct scientific impact, these studies will hold promise for several important applications, such as clean energy, electronic devices, and quantum information, and will provide economic opportunities as these technologies mature towards manufacture. We intend that our research will stimulate Canadian industrial partners to use some of our research results in the next generation of smart devices. The public will benefit from these advanced devices through increased energy efficiency and improved computational capabilities.