Controlling Magnetic Excitation Pathways via Molecular Design of Anisotropic Dipolar Spin Arrays

University Of California-San Diego, La Jolla CA

Investigators

Abstract

With support from the Chemical Structure, Dynamics & Mechanisms-B Program of the Chemistry Division, Jeffrey D. Rinehart of the Department of Chemistry and Biochemistry at the University of California, San Diego and his research team will work toward the design of magnetic interactions at the single molecule level. The team is targeting a specific set of materials that interact via intuitive and controllable mechanisms akin to normal bar magnets, despite their quantum mechanical nature. Access to these new materials has the potential to offer new avenues to the design of quantum spin interactions from the bottom up. The insight garnered from the group’s research will be used to hone fundamental models of spin relaxation and offer new entanglement mechanisms in quantum information science. This project combines subjects of inorganic, organic, theoretical, and computational chemistry and will be conducted primarily by graduate and undergraduate students at University of California, San Diego. Outreach within the scope of this project will be a collaboration with the Preuss School UC San Diego, a charter school for middle and high school low-income scholars with goals to become first-generation college students. Controlling the spin wavefunction of high moment, high anisotropy lanthanide-based molecules requires broadly applicable and feasibly implementable synthetic guidelines both to optimize desired magnetic properties in distinct units and to extend into materials of higher dimensionality. Many approaches have been pursued in this regard, including optimizing the crystal field to maximize single-ion anisotropy and promoting strong orbital exchange interactions between magnetic metal centers. Emphasizing control and versatility, this work attempts to develop a general strategy to emergent complexity through a building block approach based on the magnetic dipolar interaction between highly anisotropic units. Preliminary work has established that magnetic orientational anisotropy is consistently and predictably enforced for an erbium ion (Er3+) when bound to a cyclooctatetraene dianion, leaving other ligand sites available to establish connectivity. The predictable magnitude and direction of the magnetic moment allow intuitive design of through-space dipolar interaction pathways. The synthetic accessibility and flexibility of the magnetic building unit should allow for tight control of molecular structure to modify, test, and describe this interaction across symmetry, angular, and dimensional parameter space, creating the potential for a wavefunction-by-design approach to molecular spin dynamics. 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.