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MA: Fachverband Magnetismus

MA 27: Frustrated Magnets I

MA 27.1: Vortrag

Mittwoch, 20. März 2024, 15:00–15:15, H 2013

Spin-wave dynamics in rouaite, Cu₂(NO₃)(OD)₃ — •Dmytro S. Inosov¹, Aswathi M. Chakkingal¹, Anton A. Kulbakov¹, J. Ross Stewart², and Darren C. Peets¹ — ¹Institut für Festkörper- und Materialphysik, Fakultät Physik, TU Dresden — ²ISIS neutron source, Rutherford Appleton Laboratory, UK

Cu₂(NO₃)(OH)₃ (mineral name: rouaite) is a quasi-1D quantum spin system with structural similarity to botallackite, in which spinon-magnon mixing has recently been reported by H. Zhang et al. [Phys. Rev. Lett. 125 (2020), 037204]. It contains highly distorted triangular-lattice layers composed of alternating ferro- and antiferromagnetic spin-1/2 chains. The magnetic excitation spectrum of synthetic deuterated Cu₂(NO₃)(OD)₃ single crystals, measured by inelastic neutron scattering, reveals collective excitations with magnon bandwidths of ∼11, 1.3 and 0.05 meV in the intrachain, interchain and interlayer directions, respectively, and a spin gap of 0.2 meV. This suggests a hierarchy of exchange interactions at the boundary between quasi-1D and quasi-2D spin systems: While interchain interactions are apparently sufficient to suppress the spinon continuum, some spin-wave branches still show anomalous broadening, reminiscent of the fractionalized behavior in 1D spin chains.

Keywords: frustrated low-dimensional magnets; fractionalized spin excitations; spinons; quantum spin chains; inelastic neutron scattering