CAREER: Monostructural Topological Spin-Insulatronics

NONTECHNICAL SUMMARY

This CAREER award supports integrated research and education endeavors to discover and understand new physics enabling electronic devices to operate efficiently without incurring undesirable waste heat. Miniaturization of electronic devices is essential to the advancement of future technology. Down to the nanometer scale, however, further progress is hurdled by the low control efficiency, soaring heat, and complexity of integration.

Recent discoveries of magnetic topological materials bring about exciting opportunities to fundamentally address these problems, thanks to their unique physical characteristics. This project conducts a timely investigation in response to the pressing need for low-dissipation devices by inquiring into the microscopic physics of the emerging classes of topological materials, intending to lay a solid physical foundation for non-dissipative devices featuring a (theoretical) 100% power conversion and vanishing heat production.

In addition, the project explores a transformative alternation of the conventional spin-based electronics, such that a single material unit on its own can function as both driver and oscillator, hence obviating the need to develop complex heterostructures and interfaces. These compelling properties, bolstered by the intriguing physics behind the intertwined electronic and magnetic structures, hold potential in creating disruptive technology and could even revolutionize the basic architecture of modern computers.

The research project is complemented by educational activities to train both graduate and undergraduate students for theoretical research. The PI will organize a special seminar named “Condensed Matters Matter” targeting undergraduate students of diverse backgrounds to nurture their curiosity in condensed matter physics with an accessible level of introduction and an enhanced exposure to the latest discoveries.

The PI will also develop a new undergraduate course on MATHEMATICA programming for solving real problems in physical sciences and engineering. TECHNICAL SUMMARY

This CAREER award funds theoretical research and educational activities to achieve non-dissipative spintronics using a single magnetic material which can drive itself without relying on foreign components. Traditional paradigms of electrical control of magnetism involve engineered heterostructures in which magnetic dynamics is controlled by spin angular momenta generated from charge currents outside of the magnetic material.

Such a setup is extremely inefficient in serving its purpose because of the inhibited interfacial spin transfer and the inevitable Joule heating effect.

The PI and his team pursue a new paradigm of spintronics based on monostructural systems (i.e., single material platforms) free of interfaces and devoid of Joule heating from a theoretical perspective. The project strives to unravel the microscopic origins of the intricate interplay between topological electrons and magnetic dynamics enabled by the spin-orbit interactions, among other relevant degrees of freedom, in intrinsic magnetic topological insulators and other exotic phases of matter.

The project seeks to quantify the non-trivial spin-orbit torques driven by pure voltages, the dynamical consequences that follow, and the underlying symmetry principles. Besides establishing an in-depth understanding of the unprecedented physical behavior of monostructural spintronics, the project also seeks to make experimentally verifiable predictions and develop a theoretical toolbox for proper experimental designs.

This award also supports educational activities which include mentoring graduate students and providing unique opportunities for undergraduate students to participate in real research at an early stage. In addition, the PI will organize a special seminar named “Condensed Matters Matter” targeting undergraduate students of diverse backgrounds to nurture their curiosity in condensed matter physics with an accessible level of introduction and an enhanced exposure to the latest discoveries.

The PI will also develop a new course at senior undergraduate level to teach problem-solving skills in physical sciences and engineering using MATHEMATICA software.

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.