Microscopic Investigation of Quantum Materials

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The main focus of my research is in understanding the non-intuitive quantum behavior of solids. We specialize in cryogenic NMR (Nuclear Magnetic Resonance), and conduct microscopic investigations of a wide range of quantum materials with basic scientific interests as well as long-term potential for technological innovations, e.g. iron-based high temperature superconductors, spin-liquids, dilute magnetic semiconductors (DMS), and graphene. NMR is good at gaining deep insight into why electrons behave the way they do at microscopic levels. The overarching theme that encompasses all of our projects is therefore in answering: "How does it happen?" For example, iron-pnictides can superconduct without electrical resistance below 55 K; how can electrons form superconducting Cooper pairs with singlet spins, even though iron is a ferromagnet with parallel spins? DMS exhibit ferromagnetic behavior above ~100 K, with the prospect for spintronics applications in the future; how do dilute magnetic moments interact with each other in semiconductors with such large energy scales? To address these curiosity-based questions with the potential for major impacts on technologies, we conduct in-house research in my exceptionally well-equipped cryogenic NMR laboratory. My students have unlimited access to our Oxford top-loading dilution refrigerator (base temperature 9 mK), Janis top-loading helium-3 cryostat (base temperature 350 mK), three types of superconducting magnets (up to 16 Tesla), and three NMR spectrometers, and drive our high-profile research projects with world-class collaborators. My laboratory thus provides students with scientific research training and versatile problem solving skills for their future employments through the designing, manufacturing, computer interfacing and maintenance of our equipment. In the coming 5 years, I plan to extend our research operation both in terms of the group size and scope, by expanding into new and exciting directions of research such as DMS and graphene, while maintaining our international presence in unconventional superconductivity and quantum magnetism.