Optical studies of quantum materials

这项研究计划的目标有两个：在新材料系统中发现新的物理，并探索这些材料的潜在应用，这些材料提供比现有技术更高的性能。我的团队将建立和开发先进的光学技术来探测并最终控制新材料中的量子自由度。前两个靶系统是二维原子稀薄的过渡金属二卤化物(TMD)和拓扑Weyl半金属(WSM)。这些新兴的材料家族目前引起了人们的极大兴趣，因为它们为探索新的物理提供了新的游乐场。*最近发现的单层TMD(如MoS2和WSe2)类似于石墨烯，因为它们是具有六角蜂窝结构的2D材料。然而，与石墨烯不同的是，TMD具有半导体带隙。TMDS的一个重要特征是，除了自旋自由度外，电子还有一个额外的二进制量子自由度，称为谷磁矩。与自转类似，山谷的自由度也可以由光控制。这种非凡的性质使这些2D半导体成为实现新型光-物质耦合的理想平台，包括耦合的自旋和山谷自由度以及潜在的基于自旋和山谷的电子和信息处理应用。我的研究计划的第一步是使用最先进的光学技术测量这些激发的TMD中的自旋-山谷耦合动力学和输运性质。*WSM是一类新的拓扑非平凡的量子材料。WSM中的低能激发行为类似于粒子物理中的Weyl费米子。韦尔费米子是一种带有一定手性的无质量费米子，是费米子的最基本形式。我的团队将探索韦尔费米子的光学动力学，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性质，可能会应用到未来的电子和光子设备中。*该研究计划将加深我们对这些奇异材料的基本物理的理解，并为我们提供关于自旋、山谷和Weyl费米子的驰豫机制和输运性质以及光-物质相互作用强度的精确知识。除了直接的科学影响，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提供前景，并将在这些技术成熟到制造的过程中提供经济机会。我们打算，我们的研究将刺激加拿大的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。公众将通过提高能效和改进计算能力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.