Research Projects

Spintronics, leveraging electron spin alongside charge, offers the potential to revolutionize electronics by enhancing efficiency, speed, and storage density. Magnetic random access memory (MRAM), for instance, utilizes electron spin for non-volatile data storage, while spintronics also holds promise for low-power computing and quantum computing. However, the advancement of spintronics hinges on efficient spin detection especially in its nonequilibrium state. While equilibrium spin detection provides foundational knowledge, nonequilibrium spin detection is crucial for practical applications like the spin Hall effect and SOT-based MRAM. ___Topological quantum materials (TQMs) like Weyl semimetals and topological insulators offer unique platforms for exploring spintronic phenomena. However, electrically detecting spin in these materials remains challenging. Optical techniques such as ARPES and spin galvanic effects have demonstrated the generation of helicity-dependent spin currents, there has been a lack of quantitative measurement of electrically driven spin currents. Consequently, determining spin Hall angle from these measurements remains elusive. Electrical detection methods with ferromagnetic contacts in heterostructure devices, while promising, have so far been unable to probe the out-of-plane component of the spin texture. Novel techniques for detecting nonequilibrium spin are critically needed. ___The primary objective of this research is to address the critical gap in nonequilibrium spin detection techniques, particularly in topological quantum materials. By developing a novel electronic method, we aim to accurately measure and visualize three-dimensional nonequilibrium spin textures, including both in-plane and out-of-plane components. We will develop a low-temperature and high-magnetic field measurement setup to accurately measure electrical signals across a wide temperature range (2-300 K). Using this setup, we can directly map the spin texture of various different types of materials through nonlinear transport measurements. This capability will enable us to quantify key spin-related properties and provide essential insights into the fundamental physics of spin transport in these materials. Furthermore, we will explore the engineering of quantum properties in topological materials to enhance spin polarization and optimize device performance. ___This research introduces a novel electronic method to detect and characterize three-dimensional nonequilibrium spin textures in topological quantum materials. By leveraging material engineering techniques and experimental data, the research culminates in the development of a functional SOT-based spintronic device capable of utilizing both in-plane and out-of-plane spin polarization. These advancements will significantly contribute to the advancement of spintronics, deepen our understanding of topological quantum materials, and pave the way for the development of practical spintronic devices.