Grants and Contributions:

Grant or Award spanning more than one fiscal year. (2017-2018 to 2022-2023)

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. MoS 2 , and WSe 2 ) 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.