Career Spin Polarized Transport and Spintronic Devices

Intellectual Merit The objective of this research is to formulate a theoretical framework for spin-polarized transport in ferromagnetic heterojunctions and, by developing modeling tools, to propose and critically assess novel spintronic devices. Information stored in magnetic regions, using different orientations of the magnetization, can be preserved even without supplying any external power, opening possibilities for low-power and non-volatile applications. However, the existing commercial spintronic devices, based on the magnetoresistive effects, utilize only a small fraction of potential spin-based applications. In dilute magnetic semiconductors and in nonmagnetic semiconductor/metallic ferromagnet junctions ferromagnetism can be optically and electrically tuned thus enabling novel classes of spin transistors and multifunctional devices for seamless integration of memory and logic. The approach is to develop a multiscale modeling which combines drift-diffusion equations, generalized Landauer-Buttiker formalism, and first-principles density functional theory, to self-consistently treat largely varying carrier densities, strong deviations from the local charge neutrality, spin-polarized transport, and inhomogeneous ferromagnetism. Broader Impact The proposed research will be closely integrated with developing physics curricula and an extensive student training with active recruitment of underrepresented minorities through the Louis Stokes Alliance for Minority Participation for undergraduate students. The PI will develop a multidisciplinary course Fundamentals of Spintronics which will span aspects of solid-state physics, engineering, materials science, and nanotechnology. To disseminate the results of this research and provide additional exposure and training of students in spintronics and related disciplines, the PI will co-organize an international workshop on transport in nanostructures in collaborations with the Oak Ridge National Laboratory and the University of Tennessee.