Engineered antiferromagnetic materials for terahertz magnon-polaritons

University Of California-Los Angeles, Los Angeles CA

Investigators

Abstract

Nontechnical Description: Magnetic materials such as those found in disk drives are commonly used for information and data storage. Recently, there has been increased interest in using magnetic materials for data processing and transmission, as well as for quantum computing, as these materials consume significantly less power than conventional electronics. This research focuses on a specific type of magnetic material that oscillates at ultra high frequencies (approximately a trillion cycles per second) and responds very quickly to external stimuli; these properties make it a useful building block for very fast magnetoelectronic devices. It has traditionally been difficult to generate or control such rapid oscillations in magnetization, especially using the standard electronic controls used in most circuits. A central goal of this project is to lay the groundwork for a new class of materials and devices in which one could, for example, control the magnetization through alternate methods such as with light, using low-power lasers. As a part of the project, training of graduate and undergraduate students occurs through involvement in the research, and recruitment and retention of underrepresented minorities to engineering occurs through participation in a targeted research project course within the research lab. Technical Description: The goal of this project is the development of engineered hybrid antiferromagnetic/optoelectronic materials for the realization of strongly-coupled intersubband-magnon-polariton systems. The intellectual merit lies in the novel realization of a tripartite intersubband-magnon-photon polariton quasi-particle. Specifically, the "light" component of the polariton is carried by a specially engineered electromagnetic structure known as a metamaterial. The "matter" part of the polariton is carried by a magnon, i.e. a magnetization wave in an antiferromagnetic material. Third, the system is further coupled to another "matter" part - quantum-mechanical transitions of electrons confined within semiconductor quantum wells. Key research goals include engineering magnetic materials and structures so that all of the constituent resonances occur at similar frequencies at 1 terahertz and above, as well as maximizing the photon-magnon coupling strength. Furthermore, since the intersubband electronic system can supply gain when a population inversion is created via electrical pumping, this opens the opportunity for magnon polariton amplification and lasing. The broader impacts are addressed at several levels including undergraduate and graduate research experiences, dissemination of results, technology advancement, outreach to underrepresented minorities (URMs), and industrial interaction. Outreach to URM occurs through the PI's development of research projects for a course designed for the recruitment and retention of URM engineering freshmen. 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.