NSF Award
2418438
Non-technical Description:<br/>Quantum information technologies rely on quantum entanglement, or the intrinsic linking of one quantum object to another. An important research objective is to gain a fundamental understanding of many-body quantum entanglement involving large numbers of quantum objects. Certain magnetic materials known as geometrically frustrated magnets provide a valuable platform for this topic of study because they may exhibit many-body entanglement at low temperature. This project advances the search for promising quantum-entangled frustrated magnets through a systematic investigation of the role of atomic-scale disorder in promoting or hindering many-body entanglement. The results illuminate strategies for utilizing disorder to promote quantum-entangled ground states and contribute to a deeper understanding of many-body quantum entanglement in general. These research activities are integrated into education and outreach efforts including intensive undergraduate mentoring, summer research internships for diverse students, and a new organization called the Physics Breakfast Club that supports regional high-school physics teachers by building community and providing teaching resources.<br/> <br/>Technical Description:<br/>Recent work suggests that disorder in certain types of frustrated magnets can stabilize entangled magnetic states such as a quantum spin liquid. This project explores that idea in the context of rare-earth pyrochlore compounds with mixed atomic species on the nonmagnetic metal/metalloid site. The level of random disorder can be controlled by the size mismatch of the different atomic species, allowing a systematic investigation of the influence of disorder on the formation of a quantum spin liquid or a related phase in disordered pyrochlore compounds. The goals are to develop guiding principles for utilizing disorder as a tool for stabilizing entangled magnetic states and evaluate the potential of disordered pyrochlores for achieving these states. The magnetic and structural properties of the materials are characterized by state-of-the-art techniques including x-ray and neutron total scattering, muon spin spectroscopy, and inelastic neutron scattering. This multi-modal methodological approach is ideally suited to gaining a comprehensive understanding of the local disorder and its effect on the magnetism in pyrochlore compounds, while also providing a template for similar studies on other materials in the future.<br/><br/>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.
