The remarkable advances in computing and communications technologies in recent decades have been based on conventional electronics whose fundamental limits are rapidly being approached. In order to meet the demands for future low-power, high-performance memory and logic devices, new physical mechanisms and advanced materials that exploit them are urgently required. A promising approach is to harness the electron spin degree of freedom in a paradigm widely known as spintronics. The key to realizing spintronics technologies is the capability to efficiently manipulate the electron spin in nanoscale devices. This research program seeks a fundamental understanding of exciting new phenomena that emerge at interfaces between magnetic and nonmagnetic materials, which offer powerful new mechanisms to manipulate electron spins. The fundamental research will have broad technological impact by enabling new classes of spintronic devices for ultralow-power, high-performance computation and mass data storage, significantly impacting mobile computing and global energy efficiency. The program will train undergraduate and graduate students in advanced nanotechnologies, and provide enrichment through international collaborations. Research, education, and outreach are highly integrated by teaming graduate students with undergraduates, local high school teachers and underrepresented students. Educational media including instructional laboratory modules and course materials will be developed and disseminated broadly using the MITx/EdX online educational platform.
This research program will provide a fundamental understanding of unconventional current-induced torques and chiral spin textures that arise in ultrathin ferromagnetic heterostructures with broken inversion symmetry and strong spin-orbit coupling. The program aims to (1) quantitatively and systematically characterize spin-orbit torques in ferromagnet/heavy metal bilayers to identify their dependence on interface materials and structure, (2) provide a mechanistic understanding of magnetization switching and magnetic domain wall motion in the presence of strong spin-orbit coupling, and (3) establish the materials design principles necessary to optimize these phenomena for spintronic devices. Experiments focus on transition metals and alloys that order well above room temperature, interfaced with nonmagnetic heavy metals and oxide dielectrics that are amenable to integration with conventional semiconductor fabrication processes. The intellectual merits of these fundamental studies include important new insights into surface and interface magnetism, the quantum-mechanical effects of broken symmetries in nanoscale systems, and coupling between the charge and spin degrees of freedom. The fundamental studies will lead to revolutionary new spin-based memory and logic device capabilities, offering enhanced performance and durability with ultralow power consumption requirements.
