DCMP Seminar: Jiří Chaloupka

Department of Condensed Matter Physics invites you to lecture

Assoc. Prof. Jiří Chaloupka : Spin dynamics in Na₂Co₂TeO₆ and implications for its magnetic model

The idea of realizing the Kitaev honeycomb model in iridates and ruthenates with a d⁵ valence configuration has attracted considerable interest over the past fifteen years. In these materials, the large spin-orbit coupling combines the spin and orbital moments into pseudospins-1/2, forming the basis of the magnetic model. Due to the orbital component, the superexchange interactions among the pseudospins acquire strong bond-selective anisotropy, which manifests itself in various experiments.

In 2018, honeycomb cobaltates containing Co²⁺ ions with a 3d⁷ valence configuration were proposed as a viable alternative. Despite the significantly smaller spin-orbit coupling, strong bond-selective anisotropy of the pseudospin interactions is still expected in these systems. A number of candidate materials have been examined with the aim of quantifying their proximity to the Kitaev-model limit. In this talk, I will discuss the case of Na₂Co₂TeO₆ and the efforts to establish an appropriate magnetic model for this compound based on pseudospin dynamics observed via inelastic neutron scattering and magneto-optical measurements.