Gate-tunable spin devices based on Spin-orbitronic Engineering in Two-Dimensional Metal Monochalcogenides.

Electrons have an intrinsic spin, making them behave like tiny bar magnets. Spintronics, the control and manipulation of electron spin in a material, has led to multibillion dollar applications such as magnetic hard drives and magnetic random access memory. In many materials, electrons’ spin and spatial motion are linked, and such spin-orbit coupling has led to a variety of spintronic and quantum information applications.

Though conventionally the spin-orbit coupling strength is fixed for each material, it is highly tunable in two-dimensional materials that are only a few atomic layers in thickness. This research program takes advantage of this tunable spin-orbit coupling to create two-dimensional material spin devices, including tunable transistors that convert spin currents to charge currents, and transistors enabling long-distance spin transport.

This research will be integrated with education and training of graduate and undergraduate students for next generation of STEM task force. In addition, attention will be placed in recruiting, training, and mentoring students from under-represented groups by leveraging existing university programs, including REU, High School Tutoring and Mentoring Program in the Department of Physics, Minority Masters to PhD Bridge, and POLARIS programs, for preparing careers in academia, government and industry.

Two-dimensional materials offer new platforms for spin-orbitronic phenomena, devices, and applications with unprecedented tunability. This research program develops electrically controlled and tunable spin-orbitronic applications, using high mobility few-layer InSe that hosts large tunable spin-orbit coupling. Specifically, the thrusts include (1). demonstrating tunable spin-charge interconversion via spin Hall and Edelstein effects and their Onsager reciprocals, and with reversible spin-polarization; (2). realizing a spin helix state for long-ranged spin transport; and (3). exploring spin and charge transport in the presence of periodic 2D spin-orbit lattices that could produce topologically non-trivial magnetic textures.

These projects fundamentally advance spin-orbitronic engineering in van der Waals heterostructures, which can be utilized towards spintronic and topological devices that are tunable in operando.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.