5月14日 加州大学洛杉矶分校Qiming Shao博士学术报告:Topological spintronics: topological insulators and skyrmions


报告题目:Topological spintronics: topological insulators and skyrmions
报告人:Dr. Qiming Shao
University of California, Los Angeles (UCLA)
时间:2019年5月14日 星期二下午 2:00
地点:唐仲英楼 A213

Abstract: Ubiquitous smart devices and internet of things create tremendous data every day, shifting computing diagram towards data-driven. Computing and memory units in traditional computers are physically separated, which leads to huge energy cost and time delay. Novel computer architectures bring computing and memory units together for data-intensive applications. These memory units need to be fast, energy efficient, scalable and nonvolatile. My research concerns innovating new types of magnetic memory or spintronic devices to achieve ultrahigh energy efficiency and ultracompact size from a perspective of material and heterostructure design. Especially, we employ quantum materials to enable potentially unprecedented technological advances.
The highest energy efficiency of magnetic memory requires the largest charge-to-spin conversion efficiency that allows the minimum power to manipulate the magnetization. We utilize topological surface states of topological insulators (TIs), which have unique spin-momentum locking and thus are 100% spin-polarized. We discover giant spin-orbit torques from TIs, which are more than one order of magnitude larger than those of traditional heavy metals. We integrate TIs into room temperature magnetic memories, which promises future ultralow power dissipation.
To have the best scaling performance, we investigate emerging topological skyrmions in magnetic thin films, which are arguably the smallest spin texture in nature. While most of the skyrmions are discovered in metallic systems, insulating skyrmions are desired thanks to their lower damping and thus potentially lower power dissipation. We create first room temperature stable skyrmions in magnetic insulators by engineering heterostructures consisting of heavy metals and magnetic insulators. This new platform is essential for exploring fundamental magnon-skyrmion physics and pursuing practical applications based on insulating skyrmions.

Biography: Qiming Shao will join the Electronic and Computer Engineering department at Hong Kong University of Science and Technology (HKUST) as an assistant professor in August 2019. He is now a postdoc researcher at University of California, Los Angeles (UCLA). He received his Bachler’s degree in 2013 from Tsinghua University and his Ph.D. in early 2019 from UCLA. He has 26 publications in top peer-reviewed journals and conferences, including Science, Nature Nanotechnology, Nature Communications, Nano Letters, and International Electron Device Meeting. His Google Scholar citations > 1000 and h-index is 13. He is a recipient of 2018-2019 UCLA Dissertation Year Fellowship.

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