Frustrated Magnetism in Copper Minerals

• Applicant: Dr. Darren Peets
• Subject Area: Experimental Condensed Matter Physics ; Physical Chemistry of Solids and Surfaces, Material Characterisation
• Term: since 2021
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 452541981

This renewal proposal seeks to build on our work looking for exotic quantum magnetism in novel spin-1/2 lattices, in mineral-inspired materials. Our main target remains the maple-leaf lattice, which is intermediate between triangular and kagome, and is predicted to lie on the verge of a classically-disordered ground state. We will also investigate materials with distorted triangular lattices, distorted-triangular-lattice spin ladders, kagome lattices, and other high-symmetry structural motifs. We have already identified unexpectedly rich physics in a triangular-lattice-ladder material, which we plan to develop further. Reports of synthesis and physical measurements in most of these families remain scarce, although we have already found several new and interesting magnetic phases. During the first phase of this project, botallackite Cu2(OH)3Br was proposed to exhibit interactions between spinons and magnons, and we have now investigated another member of this family in detail, where we do not observe similar physics. This raises the question of just how one-dimensional a material needs to be to host spinon continua, or how these continua are extinguished as the dimensionality is tuned. This renewal aims to grow additional members of the family to address these questions. This project covers synthesis, basic characterization, measurement of physical properties, and identification of the magnetic order to determine the behaviour of each material. Having thus laid the foundation for understanding, we will use inelastic neutron scattering on selected systems to access the exchange interactions and understand the magnetic behaviour in the material. We also propose to cement and expand a collaboration with Hokkaido University through this renewal.

• DFG Programme: Research Grants
• International Connection: Japan
• Cooperation Partner: Professor Dr. Yoshihiko Ihara