Competing magnetic interactions and novel magnetic excitations in RMn6 Sn6 kagome metals
Prof. Rob McQueeney
Department of Physics & Astronomy
Iowa State University and Ames National Laboratory
Kagome metals hosting flat electronic bands and Dirac fermions are promising materials for the development of topological and strong correlation phenomena. RMn6 Sn6 materials (where R=rare-earth) consist of Mn kagome bilayers separated by R triangular layers. Competing magnetic interactions and magnetic anisotropies result in a variety of magnetic structures that can control and manipulate electronic bands in the kagome layer. Using inelastic neutron scattering, we discover competing interlayer interactions and show how the rare-earth ion controls the emergence of different ferrimagnetic and helical phases. We also show how thermal fluctuations of the R moment affect the stability of these magnetic phases. Finally, we provide evidence for novel itinerant flat-band and chiral magnetic excitations with the kagome layers.