Collaborative Research: High-Q Magnon Crystals and Emergent Topological Phases

University Of Iowa, Iowa City IA

Investigators

Abstract

Non-Technical Description: Magnetic materials have a long history of successful integration with high frequency electronics dating back to the invention of the radio and continuing through the present day in cell phones and other wireless communication technologies. Given this central role, it is unfortunate that our choice of materials is significantly limited by the fact that magnetic materials in nature are exceedingly rare and our ability to predict which new materials will have targeted magnetic properties is limited. This project fills that gap by employing the strategy of "materials by design" to predict and produce high quality magnetic materials that enable next-generation microwave technologies. The envisioned materials form high quality "magnetic spray paints" that can be patterned onto nearly any surface, enabling accurate micro-scale patterning for materials engineering. Down-stream technological benefits range from more power efficient microwave electronics to the potential to contribute to the development of quantum computing and quantum communication. This work helps grow our economy in the fast-moving technology sector by establishing a leadership role for the US in these emerging fields and by training students in the new techniques and new knowledge necessary to succeed in the competitive international landscape of science and innovation. Technical Description: This project exploits the ability to engineer highly coherent magnon (spin-wave) excitations in the organic-based ferrimagnet vanadium tetracyanoethylene to explore magnonic phases ranging from dilute gasses of magnon atoms (isolated magnetic micro/nanostructures) and magnon molecules (coherently coupled magnon atoms), to magnon crystals (coherently coupled arrays of atomic/molecular magnon building blocks). For example, the PIs are investigating exotic phases such as topologically protected modes in magnon crystals whose symmetry and structure are based on deterministic materials design and microscale fabrication/synthesis. This work is a joint theory/experiment collaboration, and employs both cavity and broad-band ferromagnetic resonance and magnetothermal transport measurements as well as numerical modeling and prediction of the relevant magnonic states. Both PIs have a strong track record of mentoring at all levels, and are leveraging that commitment and expertise during this program to provide an interdisciplinary and collaborative environment for the training of 3 PhD students. This research advances the field of coherent magnonics and provides a deeper understanding of the role of topology in creating and preserving coherent excitations with implications for applications ranging from next generation microwave electronics to quantum information systems. 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.